Introduction to Programming with C++
Student Lecture Workbook
Andi Toce
Last update: Sunday 26th March, 2023
Contents
I
Part One - MAC 101
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9
1.1
What is Computer Science?
1.2
What is Programming?
10
1.3
Getting Started with C++
11
1.4
Practice Questions
14
2
Numbers at Different Bases . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17
2.1
Storing Information in the Computer
17
2.2
Converting Binary, Octal and Hexadecimal to Decimal
18
2.3
Converting Decimal Numbers to Other Bases
20
2.4
Conversion Between Binary, Octal and Hexadecimal
21
2.5
Addition and Subtraction of Numbers at Different Bases
22
2.6
Practice Questions
24
3
Data Types and Operators . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 27
3.1
C++ Syntax Tokens
27
3.2
Primitive Data Types
29
3.3
Arithmetic Operations
31
3.4
Practice Questions
34
9
4
Selection Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43
4.1
Relational and Comparison Operators
43
4.2
if and if-else Statements
43
4.3
The Nested if-else Statements
46
4.4
The switch Statement
47
4.5
Logical Operators
49
4.6
Practice Questions
51
5
Repetitions Statements . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 59
5.1
C++ Loops. The while and do. . . while Statement.
59
5.2
The for loop
61
5.3
The break and continue Statements
64
5.4
Practice Questions
65
6
Functions and Parameters . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 75
6.1
What are Functions?
75
6.2
Passing a Parameter by Value or by Reference
80
6.3
Default Function Arguments
82
6.4
Function Overloading
83
6.5
Practice Questions
84
7
Variable Scope . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 93
7.1
Local and Global Variables
93
7.2
Default and Static Variables
94
7.3
Pre-defined Functions
95
7.4
Practice Questions
98
8
Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
8.1
What are Arrays
101
8.2
Initializing Arrays
102
8.3
Array Size
105
8.4
Passing Arrays to Functions
106
8.5
Characters, Strings and Arrays of Strings
108
8.6
Multi-Dimensional Arrays
109
8.7
Practice Questions
111
9
Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
9.1
What are Pointers?
121
9.2
Arrays and Pointer Arithmetic
122
10
Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 125
10.1
What are Structures?
125
10.2
Structure Composition
127
10.3
Arrays of Structures
128
10.4
Passing Structures to Functions
129
11
Introduction to Classes . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 131
11.1
Objects
131
11.2
Classes
132
11.3
The First Example
132
12
Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
12.1
How C++ Stores Text?
135
12.2
C-style String Functions
137
12.3
The <string> Class
138
13
Basic Sorting Algorithms . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 143
13.1
Sorting Algorithms
II
143
Part Two - MAC 125
14
Classes and Objects (continued...) . . . . . . . . . . . . . . . . . . . . . . . . . . . 149
14.1
Constructors
150
14.2
Destructors
152
14.3
Separating Content in Different Files
153
14.4
Constant Objects
155
14.5
Member Initializers
156
14.6
Class Composition
157
15
Classes, Pointers, and Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 159
15.1
Pointers Revisited
159
15.2
Pointers and Some Special Operators
160
15.3
Arrays and Pointers
160
15.4
The this Keyword
162
15.5
Operator Overloading
163
16
Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 165
16.1
Recursive Functions
165
16.2
More on Recursion
169
16.3
Practice Questions
172
17
Inheritance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 177
17.1
Inheritance
177
17.2
Inheritance and Constructors
180
17.3
Inheriting Functionality
182
17.4
Multiple Inheritance
184
17.5
Multilevel Inheritance
185
18
Polymorphism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 187
18.1
Polymorphism and Virtual Functions
187
18.2
Abstract Classes
191
19
Templates . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 193
19.1
Background
193
19.2
Function Templates
195
19.3
Class Templates
197
20
Linked Data Structures . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 199
20.1
Linked Lists
199
20.2
Linked Lists using Classes
201
20.3
Adding and Removing Nodes
202
21
Exception Handling . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 205
21.1
Basic Exception Handling
205
21.2
Multiple Throws and Catches
208
21.3
Throwing an Exception in a Function
209
22
Standard Template Library . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 211
22.1
Iterators
211
22.2
Vectors
212
22.3
Queue Iterator Example
213
Part Three - Other Topics
III
23
File Processing . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 221
23.1
Stream Objects
A
Answers to Exercises . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 225
A.1
Chapter 1
225
A.2
Chapter 3
226
A.3
Chapter 3
228
221
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
I
Part One - MAC 101
1
Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . 9
2
Numbers at Different Bases . . . . . . . . . . . 17
3
Data Types and Operators . . . . . . . . . . . 27
4
Selection Statements . . . . . . . . . . . . . . . . 43
5
Repetitions Statements . . . . . . . . . . . . . . . 59
6
Functions and Parameters . . . . . . . . . . . 75
7
Variable Scope . . . . . . . . . . . . . . . . . . . . . . 93
8
Arrays . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101
9
Pointers . . . . . . . . . . . . . . . . . . . . . . . . . . . . 121
10
Structures . . . . . . . . . . . . . . . . . . . . . . . . . . 125
11
Introduction to Classes . . . . . . . . . . . . . . 131
12
Strings . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 135
13
Basic Sorting Algorithms . . . . . . . . . . . . 143
1. Introduction
1.1
What is Computer Science?
Different sources give different definitions of Computer Science. Below are examples taken from
two university websites.
George Washington University: http://www.seas.gwu.edu/ simhaweb/misc/cscareers.html
What exactly is Computer Science?
Computer Science is the science of using computers to solve problems. Mostly, this involves
designing software (computer programs) and addressing fundamental scientific questions about
the nature of computation but also involves many aspects of hardware and architecting the large
computer systems that form the infrastructure of commercial and government enterprises. Computer
scientists work in many different ways: pen-and-paper theoretical work on the foundations and
fundamentals, programming work at the computer and collaborative teamwork in doing research
and solving problems.
What Computer Science is not ...
Computer Science is not about using software, such as spreadsheets (like Excel), word processors
(like Word) or image tools (like Photoshop). Many software packages are complicated to master
(such as Photoshop or Excel) and it is true that many jobs depend on expertise in using such tools,
but computer science is not about using the tools. It is not about expertise in computer games,
it is not about writing content in websites, and it is not about not about assembling computers
or knowing which computers are best buys. Edsger Dijkstra, a famous award-winning computer
scientist once said, "Computer Science is no more about computers than Astronomy is about
telescopes". Computer Science is about the principles behind building the above software packages,
about the algorithms used in computer games, about the technology behind the Internet and about
the architecture of computing devices.
Michigan Technological University: http://www.cs.mtu.edu/ john/whatiscs.html
10
Chapter 1. Introduction
Computer science is a discipline that spans theory and practice. It requires thinking both in
abstract terms and in concrete terms. The practical side of computing can be seen everywhere.
Nowadays, practically everyone is a computer user, and many people are even computer programmers. Getting computers to do what you want them to do requires intensive hands-on experience.
But computer science can be seen on a higher level, as a science of problem solving. Computer
scientists must be adept at modeling and analyzing problems. They must also be able to design
solutions and verify that they are correct. Problem solving requires precision, creativity, and careful
reasoning.
1.2
What is Programming?
What is programming?
What is a programming language?
Hierarchical layers of programming languages
1.3 Getting Started with C++
1.3
11
Getting Started with C++
Why C++ ?
•
•
•
•
•
Popular
Object-oriented language
Concise clear language
Is a good language to first learn programming
Portable
C++ IDEs (Integrated Development Environment):
•
•
•
•
•
Eclipse C++
CodeBlocks
Microsoft Visual C++
CLion
xCode (Apple devices)
Online Compilers (This should only be temporary. You need to use an IDE):
• C++ Shell. (cpp.sh). Only C++.
• JDoodle. (www.jdoodle.com). Various languages.
Installing C++ in your computer:
1. Choose a C++ editor: While I recommend using Eclipse, you can choose any C++ editor that
you feel comfortable with.
2. Install your chosen editor: For Eclipse, you can find installation guides on the internet. Search
for "Install Eclipse for C++" on YouTube, and choose a video that suits the specifications of
your computer. Follow the directions to complete the installation process.
Link (Cave of Programming) Intro discussion on pros and cons of C++, compilers and
IDEs.
Running the first program:
• Open Eclipse (or other C++ editors like CodeBlocks, Microsoft Visual C++)
• Create a new C++ project
• Create a new “HelloWorld.cpp” file
• Compile and run the file
Chapter 1. Introduction
12
Code 1.1: First C++ program
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o u t << " H e l l o World " ;
6
return 0;
7 }
Link (Cave of Programming) Hello World program.
Link (Cave of Programming) Outputting text.
What happens when we build a C++ program?
Code 1.2: A simple input-output C++ program
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
s t r i n g mystr ;
7
c o u t << " What ’ s y o u r name ? " ;
8
g e t l i n e ( cin , mystr ) ;
9
c o u t << " H e l l o " << m y s t r << " . \ n " ;
10
return 0;
11 }
1.3 Getting Started with C++
Testing, revising and optimizing a program
13
Chapter 1. Introduction
14
1.4
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) programming language:
(b) compiler:
(c) source code:
(d) algorithm:
(e) syntax and semantics:
(f) syntax error and logic error:
(g) debugging:
1.4 Practice Questions
Write a program that prints two lines of text with an empty line in between as shown
below.
Desired output:
2.
This is the first line.
This is the second line.
Click here for answer. (Try to code it first yourself!)
Write a program that prints two lines of text with an empty line in between as shown
below.
Desired output:
3.
one
two
three
Click here for answer. (Try to code it first yourself!)
Write a program that produces the output shown below.
Desired output:
4.
*
**
***
****
Click here for answer. (Try to code it first yourself!)
Write a program that produces the output shown below.
5.
Desired output:
*
***
*****
*******
Write a program that allows the user to input his/her age and prints the age on the screen.
6.
Sample output:
Enter your age: 25
You are 25 years old
Click here for answer. (Try to code it first yourself!)
15
Chapter 1. Introduction
16
Write a C++ program that allows the user to input his/her name and prints a greeting on
the screen.
7.
Sample output:
Enter your name: John
Hello John! Have a wonderful day!
2. Numbers at Different Bases
2.1
Storing Information in the Computer
In computing, the smallest unit of information storage is the bit. A bit can take on only two values,
0 or 1, and all information in a computer is stored as a sequence of bits. To make it easier to talk
about larger amounts of information, we use multiples of bits. The most common multiples are:
• Byte: a unit of 8 bits. It is the basic building block of most computer systems.
• Kilobyte (KB): a unit of a thousand bytes, or 103 bytes.
• Megabyte (MB): a unit of a million bytes, or 106 bytes.
• Gigabyte (GB): a unit of a billion bytes, or 109 bytes.
• Terabyte (TB): a unit of a trillion bytes, or 1012 bytes.
Convert 1110012 to a decimal number.
Understanding bit multiples is important for understanding the capacity and performance of
computer systems.
Chapter 2. Numbers at Different Bases
18
2.2
Converting Binary, Octal and Hexadecimal to Decimal
The base of a number system corresponds to the digits used by the system.
Base
2
8
10
16
Digits Used
0,1
0,1,2,3,4,5,6,7
0,1,2,3,4,5,6,7,8,9
0,1,2,3,4,5,6,7,8,9,A,B,C,D,E,F
Name
Binary
Octal
Decimal
Hexadecimal
Example
1012
468
10910
2A316
Decimal Equivalent
5
38
109
675
<— Watch this video to better understand why we use the binary system.
<— .... and another video.
In mathematics, we use different number bases or number systems to represent numbers. The most
commonly used number system is the decimal or base-10 system, which uses ten digits (0 to 9) to
represent numbers. However, there are other number systems as well, such as the binary (base-2),
octal (base-8), and hexadecimal (base-16) systems. Understanding how different number bases
work is important in computer science and engineering.
Consider the decimal number 2365 .
Thousands
2
103
2000
Hundreds
3
102
300
Tens
6
101
60
Ones
5
100
5
Sum = 2365
Consider the binary number 10011012 . Find the equivalent decimal number.
1
26
64
0
25
0
0
24
0
1
23
8
1
22
4
0
21
0
1
20
1
Sum = 77
10011012 = 1 × 26 + 0 × 25 + 0 × 24 + 1 × 23 + 1 × 22 + 0 × 21 + 1 × 20
= 64 + 0 + 0 + 8 + 4 + 0 + 1
= 77
10
Therefore, the equivalent decimal number of the binary number 10011012 is 7710 .
2.2 Converting Binary, Octal and Hexadecimal to Decimal
Consider the octal number 4278 . Find the equivalent decimal number.
4
82
256
2
81
16
7
80
7
Sum = 279
4278 = 7 × 80 + 2 × 81 + 4 × 82
= 7 × 1 + 2 × 8 + 4 × 64
= 7 + 16 + 256
= 279
10
Therefore, the equivalent decimal number of the octal number 4278 is 27910 .
Convert 1110012 to a decimal number.
Convert 37718 to a decimal number.
Convert 2B516 to a decimal number.
19
Chapter 2. Numbers at Different Bases
20
2.3
Converting Decimal Numbers to Other Bases
To convert a decimal number to a different base, we use the method of repeated division by the
base, while keeping track of the remainders. The remainders, read in reverse order, give us the
corresponding digits in the new base. This process can be better understood through the following
examples.
Example: convert 4310 to binary.
Divide by 2
43 / 2
21 / 2
10 / 2
5/2
2/2
1/2
Quotient
21
10
5
2
1
0
Remainder
1
1
0
1
0
1
Take the binary digits in reverse order: 4310 = 1010112
Convert 9410 to binary.
Convert 34210 to the octal equivalent.
Divide by 8
342/8
42/8
5/8
Quotient
42
5
0
Remainder
6
2
5
34210 = 5268
Convert 18910 to octal.
Convert 54210 to hexadecimal.
2.4 Conversion Between Binary, Octal and Hexadecimal
2.4
21
Conversion Between Binary, Octal and Hexadecimal
Converting between binary, octal, and hexadecimal is easier than converting to and from decimal.
Can you tell why?
Example: Convert 10110102 to octal and hexadecimal.
Octal
1
1
011
3
010
2
Binary 10110102 = Grouped 001, 011, 010
= Octal 1328
Therefore, the binary number 10110102 is equivalent to the octal number 1328 .
Hexadecimal
101
5
1010
A
10110102 = 1328 = 5A16
Convert 36178 to binary and hexadecimal.
Convert 11100012 to octal and hexadecimal.
Chapter 2. Numbers at Different Bases
22
2.5
Addition and Subtraction of Numbers at Different Bases
In this section, we will explore the addition and subtraction of numbers at different bases, focusing
on the techniques and strategies used to perform these operations efficiently and accurately.
Addition
First, a closer look at the addition of decimal values:
352410 + 69210
Let’s add the binary numbers 10011 and 11010:
1
Now try: 10111012 + 101102
Add 11001102 and 11110102
35A16 + E716
35278 + 7268
1
1
0
0
1
0
0
0
1
1
1
0
1
0
1
2.5 Addition and Subtraction of Numbers at Different Bases
Subtraction
First, a closer look at the subtraction of decimal values:
193210 − 28110
Now we subtract 110012 from 11100112
11010012 − 1011102
35A16 − E716
35278 − 7268
23
Chapter 2. Numbers at Different Bases
24
2.6
Practice Questions
1. Consider the binary number 110110012 . Find the equivalent decimal number.
2. Consider the octal number 2748 . Find the equivalent decimal number.
3. Consider the hexadecimal number AC716 . Find the equivalent decimal number.
4. Convert 28310 to the octal equivalent.
5. Convert 19810 to the corresponding hexadecimal number.
6. Convert 101100112 to octal and hexadecimal.
7. Convert 45718 to binary and hexadecimal.
8. Convert 100110112 to octal and hexadecimal.
9. Add 111001012 and 1110101102
10. Subtract 1101001012 - 10101102
2.6 Practice Questions
11. Find 35A16 + E716
12. Find 35A16 - E716
13. Find 35278 + 7268
14. Find 35278 - 7268
25
3. Data Types and Operators
3.1
C++ Syntax Tokens
In C++, tokens are the smallest individual units of a program that the compiler can understand.
Each token has a specific meaning for the compiler, and C++ has a variety of different types of
tokens, including keywords, identifiers, operators, literals, and punctuation.
Understanding the different types of C++ tokens is essential for writing correct and efficient
code, as well as for debugging errors that may arise during the compilation process.
Chapter 3. Data Types and Operators
28
Keywords in C++
Keywords are reserved words that have a specific meaning in a programming language, such as
C++. They are used to define the syntax and structure of the language, and cannot be used for any
other purpose. In C++, keywords are an essential component of the language, and it is important
for developers to have a good understanding of their usage.
The following table lists some of the most commonly used keywords in C++:
Identifiers
Identifiers are typically used to name different components of a program such as variables and
objects.
Rules for choosing identifiers:
• The first character of the name must be a letter or an underscore.
• You can only use letters, digits, or underscores in the rest of the name.
• You can’t use spaces to separate words in a function name - instead, you can either use
underscores to separate words or capitalize the first letter of words after the first word.
• ou can’t use C++ keywords as identifier names.
Which of the following is not a valid C++ identifier? Select all that apply.
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
firstInteger
first integer
first_integer
1st_integer
double
3ge4k2
$dollar
My#one
3.2 Primitive Data Types
3.2
29
Primitive Data Types
When you write a computer program or algorithm, you need to use and manipulate data. This data
can take different forms, such as numbers or text, and needs to be stored in a specific location in
the computer’s memory. This is where variables come in - they provide a way to store and access
information throughout the program.
To use variables effectively, you need to understand the different data types that can be stored. Here
are some of the most commonly used data types, along with their descriptions:
Type
Integer
Floating point
Character
String
Keyword
int
float
double
char
string
Size
at least 32 bits
at least 32 bits
at least 64 bits
at least 8 bits
varies
Example
int i=23;
float f = 23.7;
double d = 243.2;
char c = ’g’;
string s = "hello";
Code 3.1: Example of different data types and their maximum capacity.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o u t << " S i z e o f c h a r : " << s i z e o f ( c h a r ) << e n d l ;
6
char c = ’g ’ ;
7
c o u t << " Example c h a r a c t e r t y p e : " << c << e n d l ;
8
9
c o u t << " S i z e o f i n t : " << s i z e o f ( i n t ) << e n d l ;
10
i n t i = 12;
11
c o u t << " Example i n t e g e r t y p e : " << i << e n d l ;
12
13
c o u t << " S i z e o f f l o a t : " << s i z e o f ( f l o a t ) << e n d l ;
14
float f = 22.3;
15
c o u t << " Example f l o a t i n g p o i n t t y p e : " << f << e n d l ;
16
17
c o u t << " S i z e o f d o u b l e : " << s i z e o f ( d o u b l e ) << e n d l ;
18
double d = 125.345;
19
c o u t << " Example d o u b l e p r e c i s i o n t y p e : " << d << e n d l ;
20
21
return 0;
22 }
<— Click here for an extended version of this program.
30
Chapter 3. Data Types and Operators
Code 3.2: An input-output program with integers.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
int i ;
6
c o u t << " P l e a s e e n t e r an i n t e g e r v a l u e : " ;
7
c i n >> i ;
8
c o u t << " The v a l u e you e n t e r e d i s " << i ;
9
return 0;
10 }
Enter different numeric and non-numeric values of different sizes as input. What do you
notice?
What is the largest unsigned integer that can be represented with 32 bits?
What is the largest unsigned integer that can be represented with 64 bits?
<— Video Link (Cave of Programming) Variables.
<— Video Link (Cave of Programming) User Input.
<— Video Link (Cave of Programming) Integer Variables.
<— Video Link (Cave of Programming) Floating Point Variables.
3.3 Arithmetic Operations
3.3
31
Arithmetic Operations
Basic C++ arithmetic binary operators:
Operation
Addition
Subtraction
Multiplication
Division
Modulus
Parenthesis
C++ Operator
+
*
/
%
()
Example
H+3
A-B
3*D
7/5
10 % 3
(a + 2) - 5
Code 3.3: A program that adds two numbers:
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t n1 , n2 , sum ;
6
7
c o u t << " E n t e r f i r s t i n t e g e r : " ;
8
c i n >> n1 ;
9
10
c o u t << " E n t e r s e c o n d i n t e g e r : " ;
11
c i n >> n2 ;
12
13
sum = n1 + n2 ;
14
c o u t << "Sum i s " << sum << e n d l ;
15
16
return 0;
17 }
(From book) Write a program that reads a four-digit integer, such as 1998, and then
displays it, one digit per line. Your prompt should tell the user to enter a four-digit
integer. You can then assume that the user follows directions. Hint: Use the division and
remainder operators.
Desired output:
Enter a four-digit number: 1998
1
9
9
8
32
Chapter 3. Data Types and Operators
Code 3.4: A program that finds the average of two numbers
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
d o u b l e d1 ;
7
c o u t << " E n t e r t h e f i r s t number : " ;
8
c i n >> d1 ;
9
10
d o u b l e d2 ;
11
c o u t << " E n t e r t h e s e c o n d number : " ;
12
c i n >> d2 ;
13
14
c o u t << " The a v e r a g e v a l u e i s " << ( d1+d2 ) / 2 ;
15
16
return 0;
17 }
Code 3.5: A program using characters
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
c h a r myChar = ’A ’ ;
7
c o u t << " The i n i t i a l c h a r a c t e r v a l u e i s : " << myChar << e n d l ;
8
9
myChar = myChar + 1 ;
10
c o u t << " The c h a r a c t e r v a l u e i s now : " << myChar ;
11
12
return 0;
13 }
3.3 Arithmetic Operations
Basic C++ compound operators:
Expresion
x+=5;
x-=y;
x*= y+2;
x/=2;
Equivalent to
x=x+5;
x=x-y;
x=x*(y+2);
x=x/2;
Increment and decrement operators:
Expresion
++x;
x++
- -x;
x- -;
Similar to
x=x+1;
x=x+1;
x=x-1;
x=x-1;
Code 3.6: Unary increment example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
int x, y;
6
7
c o u t << " Unary P r e f i x Example : " << e n d l ;
8
x = 5;
9
y = ++x ;
10
c o u t << " x i s : " << x << e n d l ;
11
c o u t << " y i s : " << y << e n d l << e n d l ;
12
13
c o u t << " Unary S u f f i x Example : " << e n d l ;
14
x = 5;
15
y = x ++;
16
c o u t << " x i s : " << x << e n d l ;
17
c o u t << " y i s : " << y << e n d l ;
18
19
return 0;
20 }
<— Get code and some explanations here.
33
Chapter 3. Data Types and Operators
34
3.4
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) variable:
(b) identifier:
(c) keyword:
(d) statement:
(e) declaring a variable:
(f) initializing a variable:
(g) assignment statement:
Click here for answer.
3.4 Practice Questions
35
2. True-False questions – circle your choice.
(a) All variables must be declared before being used. ( True - False )
(b) C++ considers the variable number and NUMBER to be identical. ( True - False )
(c) The arithmetic operators *, /, +, and – have the same level of precedence. ( True - False )
(d) The statement cout « “a = 5;” ; is a typical assignment statement. ( True - False )
(e) The statements n +=2; and n = n+2; have the exact same outcome. ( True - False )
(f) The size of the int data type is guaranteed to be 4 bytes on all platforms. ( True - False )
(g) The double data type can hold larger values than the float data type. ( True - False )
(h) C++ has a built-in data type for representing Boolean values. (True - False)
(i) The "sizeof" operator in C++ returns the number of bytes occupied by a variable.
( True - False )
Click here for answer.
3. Assuming that x is equal to 6, which of the following statements will not result in y containing
the value 7 after execution? Select ALL that apply.
(a) y = 7;
(b) y = ++x;
(c) y = x++;
(d) y = x + 1;
(e) y = x + 8 / 2;
(f) y = (x + 8) / 2;
4. Which of the following is not a valid C++ identifier? Choose all that apply.
(a) myNumber
(b) my number
(c) my_number
(d) 1st_number
Chapter 3. Data Types and Operators
36
(e) float
(f) w3e5r6t7
(g) &number
(h) my+number
5. A variable that can have values only in the range 0 to 65535 is a:
(a) four – byte integer
(b) four – byte unsigned integer
(c) two – byte integer
(d) two – byte unsigned integer
Click here for answer.
6. Given the algebraic expression 2x2 − 5x + 2, which of the following is (are) correct C++
statements for the equation. Circle all that apply.
(a) y = 2 * x * x – 5 * x + 2
(b) y = 2 * x * x – 5 * (x + 2)
(c) y = (2 * x * x )– (5 * x) + 2
(d) y = 2 * x * (x – 5) * x + 2
7. What is the largest unsigned integer that can be represented with 32 bits and 64 bits?
Click here for answer.
8. What is the largest signed integer that can be represented with 32 bits and 64 bits?
9. Which of the following is NOT a valid C++ data type? Circle your choice clearly.
(a)
(b)
(c)
(d)
int
char
double
number
3.4 Practice Questions
37
10. Write four different C++ statements that each adds one to variable x. Embed the statements
in a small c++ program for testing.
Click here for answer.
11. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t x = 13;
6
i n t y = 3;
7
c o u t << " Summary o f R e s u l t s : " << e n d l ;
8
c o u t << x + y << e n d l ;
9
c o u t << x − y << e n d l ;
10
c o u t << x / y << e n d l ;
11
c o u t << x * y << e n d l ;
12
c o u t << x % y << e n d l ;
13
14
return 0;
15 }
Write exact output here:
Chapter 3. Data Types and Operators
38
12. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t x = 7 , y =10;
6
c o u t << x++ << " " << ++y << e n d l ;
7
c o u t << x << " " << y << e n d l ;
8
c o u t <<x−− << " " << −−y << e n d l ;
9
c o u t << x << " " << y << e n d l ;
10
c o u t << x / y << e n d l ;
11
c o u t << x % y << e n d l ;
12
13
return 0;
14 }
Write exact output here:
13. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o u t << " S i z e o f c h a r : " << s i z e o f ( c h a r ) << e n d l ;
6
c o u t << " S i z e o f i n t : " << s i z e o f ( i n t ) << e n d l ;
7
c o u t << " S i z e o f f l o a t : " << s i z e o f ( f l o a t ) << e n d l ;
8
c o u t << " S i z e o f d o u b l e : " << s i z e o f ( d o u b l e ) << e n d l ;
9
10
return 0;
11 }
Write exact output here:
3.4 Practice Questions
39
14. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
int x, y;
7
8
c o u t << " Unary P r e f i x
9
x = 11;
10
y = −−x ;
11
c o u t << " The v a l u e o f
12
c o u t << " The v a l u e o f
13
14
c o u t << " Unary S u f f i x
15
x = 11;
16
y = x − −;
17
c o u t << " The v a l u e o f
18
c o u t << " The v a l u e o f
19
20
return 0;
21 }
Write exact output here:
Example : " << e n d l ;
x i s : " << x << e n d l ;
y i s : " << y << e n d l << e n d l ;
Example : " << e n d l ;
x i s : " << x << e n d l ;
y i s : " << y << e n d l ;
Chapter 3. Data Types and Operators
40
15. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t x = 11;
7
double y = 6 , z = 2;
8
y = x / z;
9
x = 3 * y;
10
c o u t << " y = " << y << e n d l ;
11
c o u t << " x = " << x << e n d l ;
12
13
return 0;
14 }
Write exact output here:
16. Write a program that allows the user to input a temperature value in Celsius and prints the
corresponding temperature in Fahrenheit.
Use the following conversion formula: Fahrenheit = Celsius * 1.8 + 32.
Desired output:
Enter the temperature in Celsius: 30
The corresponding temperature in Fahrenheit is: 86
17. Write a program that allows the user to input a temperature value in Fahrenheit and prints the
corresponding temperature in Celsius.
Desired output:
Enter the temperature in Fahrenheit: 86
The corresponding temperature in Celsius is: 30
3.4 Practice Questions
41
18. Write a program that allows the user to input two integers, one for the length of the rectangle
and one for the width. The program then prints the value for the area of the rectangle.
Desired output:
Enter a number for the length: 5
Enter a number for the width: 4
The area of the rectangle is: 20
19. Write a program that allows the user to input a number for the side of a cube and prints the
value for the volume of the cube.
Desired output:
Enter a number for the side of the cube: 2.0
The volume of the cube is: 8.0
20. Write a C++ program that allows the user to input an integer value n and prints the sum of the
five consecutive integers starting with n. For example if the user enters 2 then the program
prints the sum = 20 since 2+3+4+5+6 = 20.
Desired output:
Enter the first integer value: 2
The sum is: 20
21. Write a C++ program that allows the user to input separately the number of years, months
and days for a given time period and prints the total number of days for the same time period.
For this exercise assume all months have 30 days.
Desired output:
Enter the number of years: 2
Enter the number of months: 5
Enter the number of days: 10
The time period you entered is equivalent to 880 days
Chapter 3. Data Types and Operators
42
22. Write a program that prompts the user to enter a five-digit integer and displays the sum of its
digits. Your program should also verify that the input is a valid five-digit integer.
Desired output:
Enter a five-digit number: 12345
The sum of the digits in 12345 is 15.
23. Write a C++ program that takes two integers as input and swaps their values. The program
should print on the screen the values of each variable before and after swapping.
Sample output:
Enter two integers: 7 9
Before swapping:
x=7
y=9
After swapping:
x=9
y=7
24. What is the largest signed decimal integer that can be represented with 16 bits?
25. What is the largest unsigned decimal integer that can be represented with 16 bits?
26. What is the minimum number of bits needed to represent the decimal value 1000?
4. Selection Statements
Very often we need to make a decision whether to execute one or more statements based on criteria
that need to be satisfied.
4.1
Relational and Comparison Operators
In C++ we use relational or comparison operators to compare two expressions. The result of the
comparison is either true or false. The table below lists these operators.
Operator
==
!=
<
Comparison
Equal to
Not equal to
Less than
Operator
>
<=
>=
Comparison
Greater than
Less or equal to
Greater or equal to
4.2 if and if-else Statements
The if statement format
if (condition)
statement: executed if condition is true;
Chapter 4. Selection Statements
44
Code 4.1: C++ if statement example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t x = 5;
6
i n t y = 5;
7
8
i f ( x==y )
9
c o u t << " x and y a r e e q u a l " << e n d l ;
10
11
c o u t << " Done ! " ;
12
return 0;
13 }
Change the value of x and run the program.
<— Video Link (Cave of Programming) If Statements.
The compound if statement format
if (condition){
statement1;
statement2;
statement3;
}
Code 4.2: C++ compound if statement example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t x = 5;
6
i n t y = 5;
7
8
i f ( x == y ) {
9
c o u t << " x and y a r e e q u a l \ n " ;
10
c o u t << " x i s " << x << " and y i s " << y << e n d l ;
11
}
12
c o u t << " Done ! " ;
13
return 0;
14 }
Remove the curly brackets at the beginning and the end of the if statement and run the
program.
4.2 if and if-else Statements
45
Write a program that allows the user to input three integers (not necessarily distinct) and
prints the largest of the three values.
Desired output:
Enter three integers: 5
2
1
The largest integer is: 5
The compound if-else statement format
if (condition)
statement1: executed if condition is true;
else
statement2: executed if condition is false;
Code 4.3: C++ if-else statement example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t x = 5;
6
i n t y = 6;
7
8
i f ( x == y )
9
c o u t << " x and y a r e e q u a l \ n " ;
10
else
11
c o u t << " x and y a r e n o t e q u a l \ n " ;
12
13
c o u t << " Done ! " ;
14
return 0;
15 }
<— Video Link (Cave of Programming) If Else Statements.
Write a program that inputs an integer and prints if the number is even or odd.
Desired output:
Enter an integer: 7
The number you entered is odd.
Chapter 4. Selection Statements
46
4.3
The Nested if-else Statements
Code 4.4: C++ nested if-else statement example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t sco re =0;
6
c o u t << " E n t e r S c o r e : " ;
7
c i n >> s c o r e ;
8
9
c o u t << " The Grade i s : " ;
10
i f ( s c o r e >= 90 )
11
c o u t << "A" ;
12
e l s e i f ( s c o r e >= 80 )
13
c o u t << "B" ;
14
e l s e i f ( s c o r e >= 70 )
15
c o u t << "C" ;
16
e l s e i f ( s c o r e >= 60 )
17
c o u t << "D" ;
18
else
19
c o u t << " F " ;
20
21
return 0;
22 }
<— Get code here.
Code 4.5: An alternative to if-else statement (using the ?: operator)
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t s c o r e = 0 ; / / s c o r e on exam
6
c o u t << " E n t e r S c o r e : " ;
7
c i n >> s c o r e ;
8
9
c o u t << ( s c o r e >= 60 ? " P a s s e d " : " F a i l e d " ) ;
10
return 0;
11 }
4.4 The switch Statement
4.4
47
The switch Statement
The switch statement is an alternative to if-else. It is commonly used if we have several condition
cases. It is easier to write and read.
Example switch statement compared to the equivalent if-else statement.
Code 4.6: Switch statement example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t day = 0 ;
6
c o u t << " E n t e r a number b e t w e e n 1 and 7 : " ;
7
c i n >> day ;
8
9
s w i t c h ( day ) {
10
c a s e 1 : c o u t << " Monday " ;
11
break ;
12
c a s e 2 : c o u t << " T u e s d a y " ;
13
break ;
14
c a s e 3 : c o u t << " Wednesday " ;
15
break ;
16
c a s e 4 : c o u t << " T h u r s d a y " ;
17
break ;
18
c a s e 5 : c o u t << " F r i d a y " ;
19
break ;
20
c a s e 6 : c o u t << " S a t u r d a y " ;
21
break ;
22
c a s e 7 : c o u t << " Sunday " ;
23
break ;
24
d e f a u l t : c o u t << " Not a v a l i d e n t r y " ;
25
break ;
26
}
27
return 0;
28 }
<— Get code here.
Remove the first 3 break statements and then enter 1 as an input. What do you notice?
Remove the default case. Does the program work? What can you conclude?
Write a program that does the same work as the switch example above but using a nested
if statement instead.
Chapter 4. Selection Statements
48
Characters share some similar features with integers. Characters are saved in memory as numbers.
We can use the same relational operators to compare characters. See example below.
Code 4.7: Example comparing characters
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
char f i r s t = ’b ’ ;
6
char second = ’b ’ ;
7
8
i f ( f i r s t < second )
9
c o u t << " I t l o o k s l i k e "
10
<< " comes b e f o r e "
11
e l s e i f ( second < f i r s t )
12
c o u t << " I t l o o k s l i k e "
13
<< " comes b e f o r e "
14
else
15
c o u t << f i r s t << " and "
16
<< " a r e t h e same . "
17
18
return 0;
19 }
<< f i r s t
<< s e c o n d << e n d l ;
<< s e c o n d
<< f i r s t << e n d l ;
<< s e c o n d
<< e n d l ;
Change the value of ’first’ and ’second’ and test the program.
4.5 Logical Operators
4.5
49
Logical Operators
Operator
Logical Operation
Example
!
NOT
!(2==2) // evaluates to FALSE
&&
AND
( 2==2) && (2==3) //evaluates to FALSE
||
OR
(2==2) || (2==3) //evaluates to TRUE
A
TRUE
TRUE
FALSE
FALSE
B
TRUE
FALSE
TRUE
FALSE
A && B
TRUE
FALSE
FALSE
FALSE
A
TRUE
TRUE
FALSE
FALSE
B
TRUE
FALSE
TRUE
FALSE
A || B
TRUE
TRUE
TRUE
FALSE
Code 4.8: || (OR) operator example.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
char agree ;
6
c o u t << " Would you l i k e t o meet ? ( y / n ) : " ;
7
c i n >> a g r e e ;
8
9
i f ( a g r e e == ’ y ’ | | a g r e e == ’Y ’ )
10
c o u t << " G r e a t ! ! ! " << e n d l ;
11
e l s e i f ( a g r e e == ’ n ’ | | a g r e e == ’N ’ )
12
c o u t << " S o r r y t o h e a r t h a t ! ! ! " << e n d l ;
13
else
14
c o u t << " What d i d you s a y ? " << e n d l ;
15
16
return 0;
17 }
Chapter 4. Selection Statements
50
Code 4.9: && (AND) operator example.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t number ;
6
c o u t << " I o n l y l i k e numbers b e t w e e n 10 and 2 0 . " << e n d l ;
7
c o u t << " E n t e r an i n t e g e r : " ;
8
c i n >> number ;
9
10
i f ( number >= 10 && number <= 2 0 )
11
c o u t << " You e n t e r e d " << number << " . I am happy ! " ;
12
else
13
c o u t << " I don ’ t l i k e t h e number you e n t e r e d ! " ;
14
15
return 0;
16 }
Determine whether the following expressions are true or false. Use a computer program
to verify your answers.
(a)
(b)
(c)
(d)
(e)
(f)
(4 == 4) && (4 >= 3) =
(4 == 4) || (10 < 5) =
!(4 == 4) || (10 < 5) =
!(4 == 4) || !(10 < 5) =
(3 != 4) && (10 < 15) || (4 == 5) =
(3 != 4) && (10 < 15) && (4 == 5) =
Here is a C++ program that can be used to verify the answer to each question.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o u t << b o o l a l p h a <<
6
c o u t << b o o l a l p h a <<
7
c o u t << b o o l a l p h a <<
8
c o u t << b o o l a l p h a <<
9
c o u t << b o o l a l p h a <<
10
c o u t << b o o l a l p h a <<
11
12
return 0;
13 }
( ( 4 == 4 ) &&
( ( 4 == 4 ) | |
( ! ( 4 == 4 ) | |
( ! ( 4 == 4 ) | |
( ( 3 ! = 4 ) &&
( ( 3 ! = 4 ) &&
( 4 >= 3 ) ) << e n d l ;
( 1 0 < 5 ) ) << e n d l ;
( 1 0 < 5 ) ) << e n d l ;
! ( 1 0 < 5 ) ) << e n d l ;
( 1 0 < 1 5 ) | | ( 4 == 5 ) ) << e n d l ;
( 1 0 < 1 5 ) && ( 4 == 5 ) ) << e n d l ;
4.6 Practice Questions
4.6
51
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) optimizing a program / algorithm:
(b) C++ is case sensitive:
(c) unsigned and signed integer:
(d) A program is scalable:
2. Determine whether the following expressions are true or false. Assume x=3 and y=5. Use a
computer program to verify your answers.
(a) (x <= 5) && (y == 5) =
(b) (x == y) || (y < 10) =
(c) !(x == 3) || (y != 5) =
(d) ((x % 3) == 1) || (y == 3) =
(e) (3 != 4) && (x < 2) || (y == 5)
Chapter 4. Selection Statements
52
3. What the following statements print? Assume i=1, j=2, k=3 and m=2.
(a) cout « (j == 1) « endl;
(b) cout « (j >= 1 && j < 4) « endl;
(c) cout « (j >= i || k == m) « endl;
(d) cout « (k + m < j || 3-j >= k) « endl;
(e) cout « (!(j - m)) « endl;
4. Which of the following is a selection statement? Clearly circle your answer.
(a) for
(b) if...else
(c) do...while
(d) while
5. True-False questions – Circle your choice
(a)
(b)
(c)
(d)
(e)
(f)
(g)
(h)
(i)
(j)
(k)
(l)
(m)
(n)
(o)
(p)
(q)
The AND (&&) operator stops after finding one condition to be false. ( True - False )
The OR (||) operator stops after finding one condition to be false. ( True - False )
The default portion is REQUIRED in a switch statement . ( True - False )
A switch statement can use a string as the expression to be evaluated. (False - True)
The logical NOT operator (!) can only be used with boolean values. (True - False)
The switch statement can only be used with integer and character types. (True - False)
The AND (&&) operator has higher precedence than the OR (||) operator. (True - False)
The if statement is a selection statement. (True - False)
The if-else statement is a conditional statement. (True - False)
The switch statement is a selection statement. (True - False)
The break statement is used to exit a switch statement. (True - False)
The AND (&&) operator evaluates both conditions even if the first condition is false.
(False - True)
The OR (||) operator evaluates both conditions even if the first condition is true. (False True)
The ?: operator can be used in place of an if-else statement. (True - False)
The AND (&&) operator can be used with integer values. (False - True)
The OR (||) operator can be used with integer values. (False - True)
The if-else statement can be nested within another if-else statement. (True - False)
4.6 Practice Questions
53
6. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
i n t number1 = 5 ;
7
i n t number2 = 1 2 ;
8
i n t number3 = 7 ;
9
i n t myChoice = 0 ;
10
11
myChoice = number1 ;
12
13
i f ( number2 < myChoice ) myChoice = number2 ;
14
i f ( number3 < myChoice ) myChoice = number3 ;
15
16
c o u t << "My C h o i c e i s : " << myChoice ;
17
return 0;
18 }
7. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t year = 2000;
6
7
i f ( ( y e a r % 4 == 0 && y e a r % 100 ! = 0 ) | | ( y e a r % 400 == 0 ) )
8
c o u t << y e a r << " i s a l e a p y e a r " ;
9
else
10
c o u t << y e a r << " i s n o t a l e a p y e a r " ;
11
12
return 0;
13 }
Chapter 4. Selection Statements
54
8. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t num1 = 5 , num2 = −3;
6
7
i f ( num1 > 0 && num2 > 0 )
8
c o u t << " The sum i s " << num1 + num2 ;
9
e l s e i f ( num1 <= 0 | | num2 <= 0 )
10
c o u t << " I n v a l i d i n p u t " ;
11
else
12
c o u t << " The d i f f e r e n c e i s " << num1 − num2 ;
13
14
return 0;
15 }
9. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
i n t x = 5;
7
i n t y = 3;
8
i n t z = 7;
9
10
i f ( x<=y && y<= z )
11
c o u t << "My C h o i c e i s : " << y ;
12
i f ( y<=x && x<= z )
13
c o u t << "My C h o i c e i s : " << x ;
14
i f ( x<= z && z <=y )
15
c o u t << "My C h o i c e i s : " << z ;
16
17
return 0;
18 }
4.6 Practice Questions
55
10. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
i n t x = 6;
7
i n t y = 6;
8
9
i f ( x >= y )
10
c o u t << " H e l l o " << e n d l ;
11
else
12
c o u t << " Goodbye " << e n d l ;
13
c o u t << " Done ! " ;
14
return 0;
15 }
11. Convert the following switch-statement into the equivalent if-else-statement.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
switch (x )
{
case 1 :
n =1;
break ;
case 2 :
n =2;
break ;
case 3 :
n =3;
break ;
default :
n =10;
break ;
}
Chapter 4. Selection Statements
56
12. Convert the following switch-statement into the equivalent if-else-statement.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 / / Choose day o f week p r o g r a m
5 i n t main ( )
6 {
7
i n t day = 0 ; / / day o f t h e week
8
c o u t << " E n t e r a number b e t w e e n 1 and 7 f o r t h e day o f t h e week : " ;
9
c i n >> day ;
10
11
i f ( day == 1 ) c o u t << " Monday " ;
12
e l s e i f ( day == 2 ) c o u t << " T u e s d a y " ;
13
e l s e i f ( day == 3 ) c o u t << " Wednesday " ;
14
e l s e i f ( day == 4 ) c o u t << " T h u r s d a y " ;
15
e l s e i f ( day == 5 ) c o u t << " F r i d a y " ;
16
e l s e i f ( day == 6 ) c o u t << " S a t u r d a y " ;
17
e l s e i f ( day == 7 ) c o u t << " Sunday " ;
18
e l s e c o u t << " Not a v a l i d e n t r y " ;
19
20
return 0;
21 }
13. Write a program that allows the user to input three integers (not necessarily distinct) and
prints the largest of the three values.
Desired output:
Enter three integers: 2 5 1
The largest integer is: 5
14. Write a program that allows the user to input three integers (not necessarily distinct) and
prints the median of the three values.
Desired output:
Enter three integers: 2 7 1
The median is: 2
4.6 Practice Questions
57
15. Write a program that inputs an integer and prints if the number is even or odd.
Desired output:
Enter an integer: 7
The number you entered is odd.
16. Write a C++ program that allows the user to input two integers and prints the sum, difference,
product, quotient, and remainder of the two values.
Desired output:
Enter two integers: 17 5
Sum: 22
Difference: 12
Product: 85
Quotient: 3
Remainder: 2
17. Write a C++ program that inputs a grade percentage and prints the corresponding letter grade
according to the following scale: A for percentages 90-100, B for 80-89, C for 70-79, D for
60-69, and F for percentages below 60.
Desired output:
Enter grade percentage: 83
Letter grade: B
18. Write a C++ program that inputs a number and checks if it is a palindrome (i.e., the number
reads the same forwards and backwards).
Desired output:
Enter a number: 12321
12321 is a palindrome.
19. Write a program that inputs a number between 1 and 12 inclusive and prints the corresponding
month of the year. If a different value is entered the program prints: “Not a valid entry!”.
Use the switch statement. As an alternative you can also write a different version of the
program using the if statement.
Sample output:
Enter a number between 1 and 12 for the month of the year: 2
The month you selected is: February
5. Repetitions Statements
5.1
C++ Loops. The while and do. . . while Statement.
Loops are a very important and powerful component of any programming language. It allows the
repetition of one or more statements as long as a condition is satisfied. One of the most basic loop
structures in C++ is the while statement.
The while statement format
The while statement format
while (condition)
statement;
while (condition){
statement1;
statement2;
statement3;
}
Code 5.1: Program using a loop to print numbers from 1 to 10
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t number = 1 ;
6
7
w h i l e ( number <= 1 0 ) {
8
c o u t << number << e n d l ;
9
number ++;
10
}
11
return 0;
12 }
Chapter 5. Repetitions Statements
60
Remove the statement number++; from the previous program and run it. What do you
notice?
Write a program that allows the user to enter an integer value n and prints all the positive
integers starting with n, in decreasing order.
Desired output:
Enter a positive integer: 7
The numbers in decreasing order are: 7 6 5 4 3 2 1
Write a program that allows the user to enter an integer value n and prints all the positive
even integers smaller or equal to n, in decreasing order.
Desired output:
Enter a positive integer: 7
The even numbers in decreasing order are: 6 4 2
The do. . . while statement. Is similar to the while statement. The list of statements is executed
before the condition is checked. So, the do. . . while statement is executed at least once.
The do...while statement format
do {
}
statement1;
statement2;
statement3;
while(condition);
5.2 The for loop
61
Code 5.2: Example do...while statement
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t number = 1 ;
6
7
do {
8
c o u t << number << e n d l ;
9
number ++;
10
} w h i l e ( number <= 1 0 ) ;
11
return 0;
12 }
5.2
The for loop
Let’s start by saying that everything that can be done using the for loop can also be done using the
while loop. However the for statement is more concise and more commonly used.
The for statement format
for(initializer; condition; increment){
statement1;
statement2;
}
Comparison for and while loops:
62
Chapter 5. Repetitions Statements
Code 5.3: Printing 1 to 10 using the for loop
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
f o r ( i n t number = 1 ; number <=10; number ++) {
6
c o u t << number << e n d l ;
7
}
8
return 0;
9 }
The next program calculates the factorial of a given number. What is the factorial of a
number?
Code 5.4: Using a nested for loop to calculate the factorial of a number
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
int factorial ;
6
i n t n = 10;
7
8
c o u t << "N \ t F a c t o r i a l o f N \ n " ;
9
10
f o r ( i n t i = 1 ; i <=n ; ++ i ) {
11
f a c t o r i a l =1;
12
f o r ( i n t j = 1 ; j <= i ; ++ j )
13
f a c t o r i a l *= j ;
14
c o u t << i << ’ \ t ’ << f a c t o r i a l << e n d l ;
15
}
16
return 0;
17 }
Can we optimize the code in Factorial.cpp? Do we need a nested for loop?
<— Click here for an improved version of the factorial program with explanations. Try to
answer the question above first before visiting this link.
5.2 The for loop
63
Write a program that prints the shape below using only the following print statements:
cout « “*”; and cout « endl;
Desired output:
*
**
***
****
*****
******
*******
********
Write a program that prints the following diamond shape. You may use output statements
that print a single asterisk (cout « “*”;) a single blank (cout « “ ”;) or new line (cout «
endl;). Maximize your use of repetition (with nested for structures) and minimize the
number of output statements.
Desired output:
*
***
*****
*******
*********
*******
*****
***
*
Chapter 5. Repetitions Statements
64
5.3
The break and continue Statements
The break statement when executed within any of the loop statements it causes the immediate exit
from the loop statement.
Code 5.5: Example break statement.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
f o r ( i n t number = 1 ; number <=10; number ++) {
7
i f ( number == 5 )
8
break ;
9
c o u t << number << e n d l ;
10
}
11
return 0;
12 }
The continue statement when used within any of the loop statements it causes the remaining
statements in the body of the loop to be skipped. The loop then continues with the next iteration.
Code 5.6: Example continue statement.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
f o r ( i n t number = 1 ; number <=10; number ++) {
7
i f ( number == 5 )
8
continue ;
9
c o u t << number << e n d l ;
10
}
11
return 0;
12 }
5.4 Practice Questions
5.4
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) iteration:
(b) sentinel:
(c) initializer:
(d) Nested loop:
(e) increment / decrement:
2. Which of the following is a C++ repetition statement?
(a) if
(b) if...else
(c) do...while
(d) switch
(e) repeat
65
Chapter 5. Repetitions Statements
66
3. What is wrong with the following while loop? Explain.
1
2
3
i n t x =5;
w h i l e ( x <= 1 0 )
x −=2;
4. The following code should output all even integers from 2 to 100 inclusive. Find and fix the
errors.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
counter = 2;
7
8
do {
9
c o u t << c o u n t e r << e n d l ;
10
c o u n t e r +=2;
11
} While ( c o u n t e r < 1 0 0 ) ;
12
13
return 0;
14 }
5.4 Practice Questions
67
5. The following code should output all powers of 2 between 1 and 100 (as shown in the desired
output column). Find and fix the errors.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
counter = 1;
6
do {
7
c o u n t e r +=2;
8
c o u t << c o u n t e r << e n d l ;
9
} while ( counter < 100);
10
11
return 0;
12 }
Desired output:
2
4
8
16
32
64
6. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
f o r ( i n t i = 1 ; i <=2; i = i + 1 )
7
f o r ( i n t j = 1 ; j <= 3 ; j = j + 1 )
8
c o u t << i << " − " << j << e n d l ;
9
10
return 0;
11 }
Chapter 5. Repetitions Statements
68
7. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
f o r ( i n t number = 1 ; number <10; number ++) {
7
i f ( number % 3 ! = 0 )
8
continue ;
9
c o u t << number << e n d l ;
10
}
11
return 0;
12 }
8. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
i n t number = 1 ;
7
w h i l e ( number < 1 0 ) {
8
c o u t << number << e n d l ;
9
number +=3;
10
}
11
return 0;
12 }
5.4 Practice Questions
9. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t i = 0 , j = 1 , k = 1 , sum = 0 ;
6
7
while ( i < 10){
8
c o u t << j << e n d l ;
9
sum= j +k ;
10
j =k ;
11
k=sum ;
12
i ++;
13
}
14 }
10. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
f o r ( i n t i = 1 ; i <=3; ++ i ) {
6
f o r ( i n t j = 1 ; j <=3; ++ j ) {
7
f o r ( i n t k = 1 ; k <=3; ++k )
8
c o u t << ’ * ’ ;
9
c o u t << e n d l ;
10
}
11
c o u t << e n d l ;
12
}
13
return 0;
14 }
69
70
11. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
i n t number = 1 5 ;
7
8
do {
9
c o u t << number << e n d l ;
10
number ++;
11
} w h i l e ( number <= 1 0 ) ;
12
return 0;
13 }
Chapter 5. Repetitions Statements
5.4 Practice Questions
71
12. Make only one change to the program below so that the current output changes to the desired
output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
int y;
6
f o r ( i n t i = 1 ; i <= 9 ; i ++ ) {
7
y =0;
8
f o r ( i n t j = 1 ; j <= i ; j ++ ) {
9
y += 1 ;
10
c o u t << i << " " ;
11
}
12
c o u t << e n d l ;
13
}
14
return 0;
15 }
Current output:
1
22
333
4444
55555
666666
7777777
88888888
999999999
Desired output:
1
12
123
1234
12345
123456
1234567
12345678
123456789
Chapter 5. Repetitions Statements
72
13. Write a C++ program that uses a nested loop to print the multiplication table for numbers
from 1 to 10 as shown below.
Desired output:
1
2
3
4
5
6
7
8
9
10
2
4
6
8
10
12
14
16
18
20
3
6
9
12
15
18
21
24
27
30
4
8
12
16
20
24
28
32
36
40
5
10
15
20
25
30
35
40
45
50
6
12
18
24
30
36
42
48
54
60
7
14
21
28
35
42
49
56
63
70
8
16
24
32
40
48
56
64
72
80
9
18
27
36
45
54
63
72
81
90
10
20
30
40
50
60
70
80
90
100
14. Write a program that allows the user to enter an integer value n and prints all the positive
integers starting with n, in decreasing order.
Sample output:
Enter a positive integer: 7
The numbers in decreasing order are: 7 6 5 4 3 2 1
15. Write a program that allows the user to enter an integer value n and prints all the positive
even integers smaller or equal to n, in decreasing order.
Sample output:
Enter a positive integer: 7
The even numbers in decreasing order are: 6 4 2
16. Write a program that allows the user to enter an integer value n and prints all the positive odd
integers smaller or equal to n, in decreasing order.
Sample output:
Enter a positive integer: 7
The odd numbers in decreasing order are: 7 5 3 1
5.4 Practice Questions
73
17. Write a program that allows the user to enter a positive integer value n and prints all the
integers from 1 to n and back down to 1.
Sample output:
Enter a positive integer: 5
The numbers are: 1 2 3 4 5 4 3 2 1
18. Write a program that has the output shown below and uses only one for loop. Hint: The
numbers in the second column are the factorials of the numbers in the first column.
Desired output:
1
2
3
4
5
6
1
2
6
24
120
720
6. Functions and Parameters
6.1
What are Functions?
Functions are important building blocks of computer programs. Functions are also referred to as
procedures, subroutines or methods. Each function is a group of statements that accomplish a
specific task. We will use a number of predefined functions available with C++ and we will also
design our own functions.
Components of a function
return_type
}
function_name (argument_list) {
statements
.......
return statement; (if applicable)
76
Chapter 6. Functions and Parameters
Code 6.1: A program that defines and tests a function that calculates the average of two numbers.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 / / F u n c t i o n must be d e c l a r e d b e f o r e b e i n g u s e d .
5 double average ( double x , double y ) ;
6
7 i n t main ( ) {
8
9
double a = 0 . 0 ;
10
double b = 0 . 0 ;
11
12
c o u t << " E n t e r f i r s t number : " ;
13
c i n >> a ;
14
c o u t << " E n t e r s e c o n d number : " ;
15
c i n >> b ;
16
17
/ / Call the function average ( ) .
18
c o u t << " A v e r a g e i s : " << a v e r a g e ( a , b ) << e n d l ;
19
20
return 0;
21
22 } / / end main ( )
23
24 / / Average −number f u n c t i o n d e f i n i t i o n
25 d o u b l e a v e r a g e ( d o u b l e x , d o u b l e y ) {
26
27
d o u b l e avg = ( x + y ) / 2 ;
28
r e t u r n avg ;
29
30 } / / end a v e r a g e ( ) f u n c t i o n
6.1 What are Functions?
Code 6.2: A program that defines and tests a factorial function.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int factorial ( int x );
5
6 i n t main ( ) {
7
8
i n t number ;
9
10
c o u t << " E n t e r an i n t e g e r : " ;
11
c i n >> number ;
12
13
c o u t << number << " ! = " << f a c t o r i a l ( number ) << e n d l ;
14
15
return 0;
16 } / / end main ( )
17
18 i n t f a c t o r i a l ( i n t x ) {
19
20
i n t f =1;
21
22
f o r ( i n t i = 2 ; i <=x ; i ++){
23
f *= i ;
24
}
25
26
return f ;
27
28 } / / end f a c t o r i a l ( )
77
Chapter 6. Functions and Parameters
78
Code 6.3: A program that defines and tests a function that prints the first n integers.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void p r i n t A l l I n t e g e r s ( i n t x ) ;
5
6 i n t main ( ) {
7
8
int n;
9
c o u t << " E n t e r an i n t e g e r : " ;
10
c i n >> n ;
11
12
c o u t << " The f i r s t " << n << " p o s i t i v e i n t e g e r s a r e : " << e n d l ;
13
printAllIntegers (n );
14
15
return 0;
16
17 } / / end main ( )
18
19 v o i d p r i n t A l l I n t e g e r s ( i n t x ) {
20
21
f o r ( i n t i = 1 ; i <=x ; i ++){
22
c o u t << i << e n d l ;
23
}
24
25 } / / end p r i n t A l l I n t e g e r s ( )
Write a C++ program that defines and tests a function largest(. . . .) that takes as parameters
any three integers and returns the largest of the three integers. Your output should have
the same format and should work for any integers a user enters.
Desired output:
Enter three integers: 6 15 8
The largest integer is: 15
6.1 What are Functions?
79
Code 6.4: A program that checks whether a number is prime.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
# include <iostream >
# i n c l u d e <cmath >
u s i n g namespace s t d ;
bool prime ( i n t ) ;
i n t main ( ) {
int n;
while ( t r u e ) {
c o u t << " E n t e r number ( 0 = e x i t ) : " ;
c i n >> n ;
i f ( n == 0 )
break ;
i f ( prime ( n ) )
c o u t << n << " i s p r i m e " << e n d l ;
else
c o u t << n << " i s n o t p r i m e " << e n d l ;
}
return 0;
} / / end main
bool prime ( i n t x ) {
f o r ( i n t i = 2 ; i < x ; i ++)
i f ( x % i == 0 ) r e t u r n f a l s e ;
return true ;
} / / end p r i m e ( )
<— Click here for a version of this program.
Optimize the prime-number function. Can we reduce the current number of operations?
Chapter 6. Functions and Parameters
80
Rewrite main so that it tests all the numbers from 2 to 10 (inclusive) and prints out the
results, each on a separate line. (Hint: Use a for loop, with i running from 2 to 10.)
Desired output:
2 is prime
3 is prime
4 is not prime
5 is prime
6 is not prime
7 is prime
8 is not prime
9 is not prime
10 is not prime
Write a C++ program that defines and tests a function power(base, exponent) that
takes two integers b and x and returns bx by using only multiplication. Design your own
function. Do not use the built in in function pow().Your output should have the same
format as shown below and should work for any integers.
Desired output:
Enter base: 2
Enter exponent: 3
2 to the power 3 is 8
6.2
Passing a Parameter by Value or by Reference
There are two ways to pass arguments to a function (by value or by reference). What we have done
so far is to pass the value of the parameter. We illustrate both possibilities via examples.
6.2 Passing a Parameter by Value or by Reference
81
Code 6.5: Passing by value example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t addOne ( i n t ) ;
5
6 i n t main ( ) {
7
8
i n t n = 3;
9
10
c o u t << " n b e f o r e c a l l i n g addOne ( ) : " << n << e n d l ;
11
c o u t << " V a l u e r e t u r n e d by addOne ( ) : " << addOne ( n ) << e n d l ;
12
c o u t << " n a f t e r c a l l i n g addOne ( ) i s : " << n << e n d l ;
13 }
14
15 i n t addOne ( i n t v a l u e ) {
16
v a l u e ++;
17
return value ;
18 }
Code 6.6: Passing by reference example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t addOne ( i n t & ) ;
5
6 i n t main ( ) {
7
8
i n t n = 3;
9
10
c o u t << " n b e f o r e c a l l i n g addOne ( ) : " << n << e n d l ;
11
c o u t << " V a l u e r e t u r n e d by addOne ( ) : " << addOne ( n ) << e n d l ;
12
c o u t << " n a f t e r c a l l i n g addOne ( ) i s : " << n << e n d l ;
13 }
14
15 i n t addOne ( i n t &v a l u e ) {
16
v a l u e ++;
17
return value ;
18 }
What are the pros and cons of each method?
Chapter 6. Functions and Parameters
82
6.3
Default Function Arguments
It is possible to assign default values to each of the function arguments. This allows the caller to
omit argument values. If the value is not specified by the caller, the default value will be used. See
examples below.
Code 6.7: Default arguments example - Rectangle area
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
# include <iostream >
u s i n g namespace s t d ;
i n t rArea ( i n t l e n g t h = 2 , i n t width = 1 ) ;
i n t main ( ) {
c o u t << " D e f a u l t a r e a : " << r A r e a ( ) << e n d l ;
c o u t << " l e n g t h =10 and d e f a u l t w i d t h : " << r A r e a ( 1 0 ) << e n d l ;
c o u t << " l e n g t h =10 and w i d t h = 5 : " << r A r e a ( 1 0 , 5 ) << e n d l ;
return 0;
}
i n t rArea ( i n t length , i n t width ){
r e t u r n l e n g t h * width ;
}
Can we assign a default value to only length or only width?
Code 6.8: Additional Example - Interest
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
# include <iostream >
u s i n g namespace s t d ;
double i n t e r e s t ( double p = 1000 , double r = 0 . 0 5 , double t = 1 ) ;
i n t main ( ) {
c o u t <<
<<
c o u t <<
c o u t <<
c o u t <<
" i n t e r e s t (3000 , 0.015 , 5 ) : "
i n t e r e s t ( 3 0 0 0 , 0 . 0 1 5 , 5 ) << e n d l ;
" i n t e r e s t ( 3 0 0 0 , 0 . 0 1 5 ) : " << i n t e r e s t ( 3 0 0 0 , 0 . 0 1 5 ) << e n d l ;
" i n t e r e s t ( 3 0 0 0 ) : " << i n t e r e s t ( 3 0 0 0 ) << e n d l ;
" i n t e r e s t ( ) : " << i n t e r e s t ( ) << e n d l ;
return 0;
}
double i n t e r e s t ( double p , double r , double t ){
r e t u r n p* r * t ;
}
6.4 Function Overloading
6.4
83
Function Overloading
It is possible to declare different functions using the same function identifier. These functions
however have different signatures, typically different data types. The C++ compiler will select the
version of the function that matches with the signature.
Code 6.9: Function overloading example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
# include <iostream >
u s i n g namespace s t d ;
i n t addNumbers ( i n t , i n t ) ;
d o u b l e addNumbers ( d o u b l e , d o u b l e ) ;
i n t main ( ) {
i n t xInt = 5;
i n t yInt = 7;
d o u b l e xDouble = 3 . 3 ;
d o u b l e yDouble = 2 . 4 ;
cout
cout
cout
cout
<<
<<
<<
<<
" Calling
"Sum i s :
" Calling
"Sum i s :
t h e i n t e g e r v e r s i o n . " << e n d l ;
" << addNumbers ( x I n t , y I n t ) << e n d l << e n d l ;
t h e d o u b l e v e r s i o n . " << e n d l ;
" << addNumbers ( xDouble , yDouble ) << e n d l ;
return 0;
}
i n t addNumbers ( i n t f i r s t , i n t s e c o n d ) {
c o u t << " I n s i d e t h e i n t e g e r v e r s i o n . " << e n d l ;
r e t u r n f i r s t + second ;
}
d o u b l e addNumbers ( d o u b l e f i r s t , d o u b l e s e c o n d ) {
c o u t << " I n s i d e t h e d o u b l e v e r s i o n . " << e n d l ;
r e t u r n f i r s t + second ;
}
<— Get here a similar version of the program.
Can we overload a function by changing the number of arguments?
Can we overload a function by only changing the return type?
Chapter 6. Functions and Parameters
84
6.5
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) function return type:
(b) pre-defined and user-defined functions:
(c) function arguments / parameters:
(d) function call:
(e) void return type:
(f) passing an argument by value or by reference:
(g) function overloading:
(h) default function values:
6.5 Practice Questions
(i) function header and function body:
(j) function declaration / function prototype:
2. True-False questions – Circle your choice
(a) All arguments to C++ function calls are passed by value. ( True - False )
(b) A C++ function must always return a value when called. ( True - False )
3. If an argument to a function is declared as const, then ...
(a) Function can modify the argument
(b) Function can’t modify the argument
(c) const argument to a function is not possible
(d) None of the above
85
Chapter 6. Functions and Parameters
86
4. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int f ( int b, int e );
5
6 i n t main ( ) {
7
i n t n1 = 2 , n2 = 6 ;
8
c o u t << n1 << " ^ " << n2 << " = " << f ( n1 , n2 ) << e n d l ;
9
return 0;
10 } / / end main
11
12 i n t f ( i n t b , i n t e ) {
13
i n t r e s u l t =1;
14
f o r ( i n t i = 1 ; i <= e ; i ++)
15
r e s u l t *= b ;
16
return result ;
17 }
5. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t re c ta ng le A re a ( i n t l e n g t h = 2 , i n t width = 1 ) ;
5
6 i n t main ( ) {
7
c o u t << " F i r s t R e c t a n g l e : " << r e c t a n g l e A r e a ( ) << e n d l ;
8
c o u t << " Second R e c t a n g l e : " << r e c t a n g l e A r e a ( 5 ) << e n d l ;
9
c o u t << " T h i r d R e c t a n g l e : " << r e c t a n g l e A r e a ( 1 0 , 2 ) << e n d l ;
10
return 0;
11 }
12
13 i n t r e c t a n g l e A r e a ( i n t l e n g t h , i n t w i d t h ) {
14
r e t u r n l e n g t h * width ;
15 }
6.5 Practice Questions
6. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t myFunction ( i n t ) ;
5
6 i n t main ( ) {
7
i n t number = 5 ;
8
c o u t << number << e n d l ;
9
c o u t << m y F u n c t i o n ( number ) << e n d l ;
10
c o u t << number << e n d l ;
11 }
12
13 i n t m y F u n c t i o n ( i n t v a l u e ) {
14
value *=5;
15
return value ;
16 }
7. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t myFunction ( i n t &);
5
6 i n t main ( ) {
7
i n t number = 5 ;
8
c o u t << number << e n d l ;
9
c o u t << m y F u n c t i o n ( number ) << e n d l ;
10
c o u t << number << e n d l ;
11 }
12
13 i n t m y F u n c t i o n ( i n t &v a l u e ) {
14
value *=5;
15
return value ;
16 }
87
Chapter 6. Functions and Parameters
88
8. Write a program that defines and tests function factorial(). Use a for loop for this function.
Sample output is given.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int factorial ( int x );
5
6 i n t main ( ) {
7
i n t number ;
8
c o u t << " E n t e r an i n t e g e r f o r t h e d e s i r e d f a c t o r i a l : " ;
9
c i n >> number ;
10
c o u t << number << " ! = " << f a c t o r i a l ( number ) << e n d l ;
11
return 0;
12 }
13
14 i n t f a c t o r i a l ( i n t x ) {
15
16
17
18
19
20
21 }
Sample output:
Enter an integer for the desired factorial: 5
5! = 120
6.5 Practice Questions
89
9. Write a program that defines and tests a function that prints the first n positive integers
followed by their sum. Use a while loop for this function. Sample output is given.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void p r i n t A l l I n t e g e r s ( i n t x ) ;
5
6 i n t main ( ) {
7
i n t number ;
8
c o u t << " E n t e r an I n t e g e r : " ;
9
c i n >> number ;
10
c o u t << " The f i r s t " << number << " i n t e g e r s a r e l i s t e d below : " << e n d l ;
11
p r i n t A l l I n t e g e r s ( number ) ;
12
return 0;
13 } / / end main ( ) f u n c t i o n
14
15 v o i d p r i n t A l l I n t e g e r s ( i n t x ) {
16
17
18
19
20
21
22
23 }
Sample output:
Enter an Integer: 6
The first 6 positive integers are listed below:
1
2
3
4
5
6
Sum = 21
Chapter 6. Functions and Parameters
90
10. Write a C++ program that defines and tests a function largest(. . . .) that takes as parameters
any three integers and returns the largest of the three integers.
Sample output:
Enter three integers: 6 15 8
The largest integer is: 15
11. Write a C++ program that defines and tests a function absoluteValue(. . . .) that takes as a
parameter a floating point number and returns its absolute value.
Sample output:
Enter a number: -4.25
The absolute value is: 4.25
12. Write a C++ program that defines a function reverseInt(int n) that takes as an argument a
positive integer and returns an integer with digits in reverse order. Print n before and after
reversing the digits. Your output should have the same format and should work for any
integer a user enters.
Sample output:
The value before reverse is: 425
The value after reverse is: 524
13. Write a C++ program that defines and tests a function multiplyNumbers(m,n) that takes two
positive integers m and n, computes m * n by using only addition, and returns the product.
Hint: Use iteration and notice for example that 3*2=2 +2 +2
Sample output:
Enter m: 2
Enter n: 3
2*3 = 6
6.5 Practice Questions
91
14. Write a C++ program that defines and tests a function power(base, exponent) that takes
two integers b and x and returns bx by using only multiplication. Design your own function.
Do not use the built in function pow().
Sample output:
Enter base: 2
Enter Exponent: 3
2 to the power 3 = 8
15. Write a boolean function divisibleBySeven(. . . ) definition that takes as an input an integer
and returns true if the integer is divisible by 7, false if not. Make sure you use the proper
function return type and argument list. Just write the function definition. You do not need to
write a complete C++ program.
16. Write a function isDigit(. . . ) definition that takes one argument of type char and returns a
bool value. The function returns true if the argument is a decimal digit; otherwise it returns
false. Make sure you use the proper function return type and argument list. Just write the
function definition. You do not need to write a complete C++ program.
17. Write a function multiple(. . . ) definition that determines for a pair of integers whether the
second integer is a multiple of the first. The function should take two integer arguments and
return true if the second is a multiple of the first, false otherwise. . Make sure you use the
proper function return type and argument list. Just write the function definition. You do not
need to write a complete C++ program.
7. Variable Scope
7.1
Local and Global Variables
A variable is local if it is declared inside a function. A global variable is declared outside of all
functions including main. Global variables are typically declared at the very beginning of the
program. Local variables are better choices unless there is a specific need for a global variable
shared by multiple functions.
Chapter 7. Variable Scope
94
Code 7.1: Global vs. local variables example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
# include <iostream >
u s i n g namespace s t d ;
i n t i = 1;
void f i r s t F u n c t i o n ( ) ;
void secondFunction ( ) ;
void t h i r d F u n c t i o n ( ) ;
i n t main ( ) {
i n t i = 2;
c o u t << " I n s i d e main ( ) : i = " << i << e n d l ;
firstFunction ();
secondFunction ( ) ;
thirdFunction ();
return 0;
}
void f i r s t F u n c t i o n ( ) {
i n t i = 3;
c o u t << " I n s i d e f i r s t F u n c t i o n ( ) : i = " << i << e n d l ;
}
void secondFunction ( ) {
c o u t << " I n s i d e s e c o n d F u n c t i o n ( ) : i = " << i << e n d l ;
}
void t h i r d F u n c t i o n ( ) {
i n t i = 4;
c o u t << " I n s i d e t h i r d F u n c t i o n ( ) : i = " << : : i << e n d l ;
}
<— Get a version of the code here.
7.2
Default and Static Variables
The ‘lifetime’ of a variable is determined by the storage category it belongs. The most commonly
used categories are auto (default choice) and static. An auto local variable is assigned memory
space automatically during the execution of a function. Once the function returns, the variable’s
memory space is released and made available to other processes. A static variable continues to
‘exist’ during the entire execution of the program.
7.3 Pre-defined Functions
95
Code 7.2: Example auto variable
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void t e s t ( ) ;
5
6 i n t main ( ) {
7
8
f o r ( i n t i = 1 ; i <=3; i ++)
9
test ();
10
11
return 0;
12 } / / end main ( )
13
14 v o i d t e s t ( ) {
15
16
i n t number = 0 ;
17
c o u t << " number i s : " << number << e n d l ;
18
number ++;
19
20
return ;
21 } / / end t e s t ( )
Change the local variable ‘number’ to static and run the program. What do you observe?
7.3
Pre-defined Functions
A number of pre-defined functions are already available for programmers to use. These functions
are grouped in collections called libraries. In order for the user to have access to these functions
the program should include the given library. <cmath> is an example of a library. The following
program illustrates some of its functions.
Chapter 7. Variable Scope
96
Code 7.3: Using functions from the cmath library
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
# include <iostream >
# i n c l u d e <cmath >
# i n c l u d e <iomanip >
u s i n g namespace s t d ;
i n t main ( ) {
cout
cout
cout
cout
cout
cout
cout
<<
<<
<<
<<
<<
<<
<<
f i x e d << s e t p r e c i s i o n ( 2 ) ;
" s q r t ( 1 2 . 0 ) = " << s q r t ( 1 2 . 0 ) << e n d l ;
" exp ( 1 . 0 ) = " << s e t p r e c i s i o n ( 3 ) << exp ( 1 . 0 ) << e n d l ;
" l o g ( 8 . 3 2 ) = " << l o g ( 8 . 3 2 ) << e n d l ;
" l o g ( exp ( 8 . 2 3 ) ) = " << l o g ( exp ( 8 . 2 3 ) ) << e n d l ;
" pow ( 2 , 3 ) = " << pow ( 2 , 3 ) << e n d l ;
" c o s ( 9 0 ) = " << s e t p r e c i s i o n ( 1 5 ) << c o s ( 9 0 ) << e n d l ;
return 0;
}
<— Get code here.
Code 7.4: Random number generator
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
# include <iostream >
# i n c l u d e <cmath >
# include <cstdlib >
# i n c l u d e <ctime >
u s i n g namespace s t d ;
i n t main ( ) {
int n, r ;
s r a n d ( t i m e (NULL ) ) ;
c o u t << "How many numbers do you want ? " ;
c i n >> n ;
f o r ( i n t i = 1 ; i <= n ; i ++) {
r = rand ( ) % 9 + 1;
c o u t << r << " " ;
}
return 0;
}
What is the range of numbers generated by the program?
7.3 Pre-defined Functions
97
Modify the program to generate numbers in the range [5,10].
Modify the program to generate numbers in the range [-3,25].
Modify the program to allow the user to specify the range of values to be generated.
Modify the program to display a frequency distribution of the values and graph the
results.
Sample output:
How many number do you want? 20
22632341434554333342
Value
1
2
3
4
5
6
Freq
1
4
7
5
2
1
Graph
*
****
*******
*****
**
*
Chapter 7. Variable Scope
98
7.4
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) local and global variables:
(b) Stack:
(c) scope of a variable:
(d) static variable:
2. True-False questions – Circle your choice
(a) A variable is local if it is declared inside the main function. ( True - False )
(b) A variable declared within a function is said to be local to the function. ( True - False )
3. The statement n = rand(); assigns to variable n a value between 0 and a very large positive
integer. Change the statement to assign to n a value in the following ranges.
(a) [1, 5]
(b) [5, 100]
(c) [−3, 18]
7.4 Practice Questions
99
4. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t myFunction ( ) ;
5
6 i n t main ( ) {
7
c o u t << m y F u n c t i o n ( ) << e n d l ;
8
c o u t << m y F u n c t i o n ( ) << e n d l ;
9
c o u t << m y F u n c t i o n ( ) << e n d l ;
10
return 0;
11 }
12
13 i n t m y F u n c t i o n ( ) {
14
i n t number = 0 ;
15
r e t u r n number ++;
16 }
5. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t myFunction ( ) ;
5
6 i n t main ( ) {
7
c o u t << m y F u n c t i o n ( )
8
c o u t << m y F u n c t i o n ( )
9
c o u t << m y F u n c t i o n ( )
10
return 0;
11 }
12
13 i n t m y F u n c t i o n ( ) {
14
s t a t i c i n t number =
15
r e t u r n number ++;
16 }
<< e n d l ;
<< e n d l ;
<< e n d l ;
0;
Chapter 7. Variable Scope
100
6. Write the exact output for the following code.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 char myFunction ( ) ;
5
6 i n t main ( ) {
7
c o u t << m y F u n c t i o n ( ) <<
8
c o u t << m y F u n c t i o n ( ) <<
9
c o u t << m y F u n c t i o n ( ) <<
10
return 0;
11 }
12
13 c h a r m y F u n c t i o n ( ) {
14
s t a t i c char character =
15
r e t u r n c h a r a c t e r ++;
16 }
endl ;
endl ;
endl ;
’a ’ ;
7. Write the exact output.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
# include <iostream >
u s i n g namespace s t d ;
i n t i = 7;
void f i r s t F u n c t i o n ( ) ;
void secondFunction ( ) ;
i n t main ( ) {
i n t i = 2;
c o u t << " I n s i d e main ( ) : i = " << i << e n d l ;
firstFunction ();
secondFunction ( ) ;
return 0;
}
void f i r s t F u n c t i o n ( ) {
i n t i = 5;
c o u t << " I n s i d e f i r s t F u n c t i o n ( ) : i = " << i << e n d l ;
}
void secondFunction ( ) {
c o u t << " I n s i d e s e c o n d F u n c t i o n ( ) : i = " << i << e n d l ;
}
8. Arrays
8.1
What are Arrays
An array is an ordered collection (potentially very large) of items. Arrays are indexed to allow
easier access to its elements. Arrays are powerful structures that allow the user to store multiple
data values of the same type without having to declare as many variables.
Assume we want to store 5 double data values for further processing (example find their average).
One way is to declare 5 different double variables, one for each value. This is not an efficient way
of storing data. Imagine we have to do this for a lot more data values. The following program uses
an array to store the data values and calculate the average of all these values.
Chapter 8. Arrays
102
Code 8.1: Example using arrays
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
d o u b l e myArray [ 5 ] ;
7
8
c o u t << " E n t e r v a l u e s : " << e n d l ;
9
10
f o r ( i n t i = 0 ; i < 5 ; i ++)
11
c i n >> myArray [ i ] ;
12
13
d o u b l e sum = 0 ;
14
f o r ( i n t i = 0 ; i < 5 ; i ++)
15
sum += myArray [ i ] ;
16
17
c o u t << " The A v e r a g e i s : " << sum / 5 << e n d l ;
18
return 0;
19 }
8.2
Initializing Arrays
Arrays follow the same principles regarding initialization as variables. Global numerical variables
(arrays) are all initialized to zero by default if the user does not specify any values. Local variables
must be initialized by the user otherwise they will be possibly assigned random values.
8.2 Initializing Arrays
103
Code 8.2: Initializing global and local arrays
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int globalArray [6];
5
6 i n t main ( ) {
7
8
int localArray [8];
9
10
c o u t << " G l o b a l A r r a y v a l u e s b e f o r e i n i t i a l i z i n g . " << e n d l ;
11
f o r ( i n t i = 0 ; i < 6 ; i ++)
12
c o u t << g l o b a l A r r a y [ i ] << " " ;
13
14
c o u t << e n d l << e n d l ;
15
16
c o u t << " L o c a l A r r a y v a l u e s b e f o r e i n i t i a l i z i n g . " << e n d l ;
17
f o r ( i n t i = 0 ; i < 8 ; i ++)
18
c o u t << l o c a l A r r a y [ i ] << " " ;
19
20
c o u t << e n d l << e n d l ;
21
22
int initializedLocalArray [5] = {3 ,4 ,6 ,2 ,4};
23
24
c o u t << " I n i t i a l i z e d L o c a l A r r a y v a l u e s . " << e n d l ;
25
f o r ( i n t i = 0 ; i < 5 ; i ++)
26
c o u t << i n i t i a l i z e d L o c a l A r r a y [ i ] << " " ;
27
28
return 0;
29 }
<— Get code here.
Modify the following code to use an array instead of the individually declared variables.
Does this approach improve code writing and code readability?
<— Get code here.
Chapter 8. Arrays
104
Code 8.3: Random number simulator with statistics
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
# include <iostream >
# include <cstdlib >
# i n c l u d e <ctime >
u s i n g namespace s t d ;
void keepRecord ( i n t ) ;
void d i s p l a y S t a t i s t i c s ( ) ;
i n t n1 , n2 , n3 , n4 , n5 ;
i n t main ( ) {
int n , r ;
s r a n d ( t i m e (NULL ) ) ;
c o u t << "How many numbers do you want : " ;
c i n >> n ;
f o r ( i n t i = 1 ; i <= n ; i ++) {
r = r a n d ( ) \% 5 + 1 ;
c o u t << r << " " ;
keepRecord ( r ) ;
}
c o u t << e n d l << e n d l ;
displayStatistics ();
return 0;
}
void keepRecord ( i n t value ){
switch ( value ){
c a s e 1 : n1 ++; b r e a k ;
c a s e 2 : n2 ++; b r e a k ;
c a s e 3 : n3 ++; b r e a k ;
c a s e 4 : n4 ++; b r e a k ;
c a s e 5 : n5 ++; b r e a k ;
}
}
void d i s p l a y S t a t i s t i c s ( ) {
c o u t << " V a l u e \ t " << " F r e q \ t " << " Graph " << e n d l << e n d l ;
c o u t << " 1 \ t " << n1 << " \ t " ;
f o r ( i n t i = 0 ; i <n1 ; i ++) c o u t << " * " ;
c o u t << e n d l ;
c o u t << " 2 \ t " << n2 << " \ t " ;
f o r ( i n t i = 0 ; i <n2 ; i ++) c o u t << " * " ;
c o u t << e n d l ;
c o u t << " 3 \ t " << n3 << " \ t " ;
f o r ( i n t i = 0 ; i <n3 ; i ++) c o u t << " * " ;
c o u t << e n d l ;
c o u t << " 4 \ t " << n4 << " \ t " ;
f o r ( i n t i = 0 ; i <n4 ; i ++) c o u t << " * " ;
c o u t << e n d l ;
c o u t << " 5 \ t " << n5 << " \ t " ;
f o r ( i n t i = 0 ; i <n1 ; i ++) c o u t << " * " ;
c o u t << e n d l ;
}
8.3 Array Size
8.3
105
Array Size
It is a good practice to declare a constant integer for the size of the array and use it during the
program as needed.
Code 8.4: Using constant array size example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
c o n s t i n t myArraySize = 5 ;
7
i n t myArray [ m y A r r a y S i z e ] = { 3 , 4 , 6 , 2 , 4 } ;
8
9
c o u t << " Number o f e l e m e n t s : " << m y A r r a y S i z e << e n d l ;
10
c o u t << " L i s t o f e l e m e n t s : " ;
11
f o r ( i n t i = 0 ; i < m y A r r a y S i z e ; i ++)
12
c o u t << myArray [ i ] << " " ;
13
14
return 0;
15 }
Another way of getting the array size.
Code 8.5: Calculating number of array elements
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t myArray [ 5 ] = { 3 , 4 , 6 , 2 , 4 } ;
7
8
c o u t << " A r r a y s i z e i n b y t e s : " << s i z e o f ( myArray ) << e n d l ;
9
c o u t << " F i r s t e l e m e n t s i z e : " << s i z e o f ( myArray [ 0 ] ) << e n d l ;
10
i n t s i z e = s i z e o f ( myArray ) / s i z e o f ( myArray [ 0 ] ) ;
11
c o u t << " The number o f e l e m e n t s i s : " << s i z e << e n d l ;
12
c o u t << " E l e m e n t s i n t h e a r r a y s a r e : " ;
13
f o r ( i n t i = 0 ; i < s i z e ; i ++)
14
c o u t << myArray [ i ] << " " ;
15
16
return 0;
17 }
<— Get code here.
Chapter 8. Arrays
106
8.4
Passing Arrays to Functions
In C++ arrays are passed to functions by reference. Individual elements from the array are passed
by value. See example below.
Code 8.6: Passing Arrays to Functions Example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void modifyArray ( i n t [ ] , i n t ) ;
5
6 i n t main ( ) {
7
8
const i n t arraySize = 5;
9
i n t myArray [ a r r a y S i z e ] = { 3 , 4 , 6 , 2 , 8 } ;
10
11
c o u t << " E l e m e n t s i n t h e o r i g i n a l a r r a y a r e : " << e n d l ;
12
f o r ( i n t i = 0 ; i < a r r a y S i z e ; i ++)
13
c o u t << myArray [ i ] << " " ;
14
c o u t << e n d l << e n d l ;
15
16
m o d i f y A r r a y ( myArray , a r r a y S i z e ) ;
17
18
c o u t << " E l e m e n t s i n t h e m o d i f i e d a r r a y a r e : " << e n d l ;
19
f o r ( i n t i = 0 ; i < a r r a y S i z e ; i ++)
20
c o u t << myArray [ i ] << " " ;
21
c o u t << e n d l ;
22
23
return 0;
24 } / / end main
25
26 v o i d m o d i f y A r r a y ( i n t a [ ] , i n t s i z e O f A r r a y ) {
27
f o r ( i n t i = 0 ; i < s i z e O f A r r a y ; i ++)
28
a [ i ]++;
29 } / / end m o d i f y A r r a y ( )
<— Get code here.
Add another value to the number set 3,4,6,2,8, in PassingArraysToFunctions.cpp, compile
and run the program. Does the program run? What do you observe? What can you
conclude?
Change the function signature to read void modifyArray(const int a[], int sizeOfArray).
Compile and run the program. What do you notice?
Add a ’cout’ statement that prints myArray[5]. Does it work? What do you think is
happening?
8.4 Passing Arrays to Functions
107
Write a program that uses a function largestValue(int[], int) that takes as an argument an
array of integers and the size of the array and returns the largest value in the array. Part
of the code is given. Complete the remaining code (function definition) to produce the
desired output.
Desired output format:
The largest value is: 25
Code 8.7: Class code activity
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int largestValue ( int [] , int );
5
6 i n t main ( ) {
7
8
const i n t arraySize = 10;
9
i n t myArray [ a r r a y S i z e ] = { 3 , 4 , 6 , 2 1 , 8 , 1 3 , 2 5 , 1 , 7 , 1 1 } ;
10
11
c o u t << " The l a r g e s t i n t e g e r i s : " ;
12
c o u t << l a r g e s t V a l u e ( myArray , a r r a y S i z e ) ;
13
14
return 0;
15 } / / end main
16
17 i n t l a r g e s t V a l u e ( i n t a [ ] , i n t s i z e O f A r r a y ) {
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33 } / / end l a r g e s t V a l u e ( )
Chapter 8. Arrays
108
8.5
Characters, Strings and Arrays of Strings
Code 8.8: Example illustrating different char arrays.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
char f i r s t A r r a y [ 8 ] ;
7
8
f o r ( i n t i = 0 ; i < 8 ; i ++)
9
f i r s t A r r a y [ i ]= ’ d ’ ;
10
11
c o u t << " P r i n t f i r s t A r r a y u s i n g f o r l o o p : " << e n d l ;
12
f o r ( i n t i = 0 ; i < 7 ; i ++)
13
c o u t << f i r s t A r r a y [ i ] ;
14
15
f i r s t A r r a y [7]= ’ \0 ’ ;
16
c o u t << e n d l ;
17
18
c o u t << " P r i n t f i r s t A r r a y u s i n g i d e n t i f i e r : " << e n d l ;
19
c o u t << f i r s t A r r a y << e n d l ;
20
21
c h a r s e c o n d A r r a y [ ] = { ’H ’ , ’ e ’ , ’ l ’ , ’ l ’ , ’ o ’ , ’ \ 0 ’ } ;
22
c o u t << " P r i n t s e c o n d A r r a y u s i n g f o r l o o p : " << e n d l ;
23
f o r ( i n t i = 0 ; i < 6 ; i ++)
24
c o u t << s e c o n d A r r a y [ i ] ;
25
c o u t << e n d l ;
26
27
char thirdArray [ ] = " Test " ;
28
c o u t << " P r i n t t h i r d A r r a y u s i n g f o r l o o p : " << e n d l ;
29
f o r ( i n t i = 0 ; i < 4 ; i ++)
30
c o u t << t h i r d A r r a y [ i ] ;
31
c o u t << e n d l ;
32
33
c o u t << " C h a n g i n g one d i g i t i n t h i r d a r r a y : " << e n d l ;
34
t h i r d A r r a y [ 0 ] = ’N ’ ;
35
c o u t << " P r i n t t h i r d A r r a y u s i n g f o r l o o p : " << e n d l ;
36
f o r ( i n t i = 0 ; i < 4 ; i ++)
37
c o u t << t h i r d A r r a y [ i ] ;
38
39
return 0;
40 }
<— Get code here.
Comment out the statement firstArray[7]=’\0’; . What changes do you see in the output?
8.6 Multi-Dimensional Arrays
109
Code 8.9: Array of Strings Example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
c h a r * weekDays [ 7 ] = { " Monday " , " T u e s d a y " , " Wednesday " ,
7
" T h u r s d a y " , " F r i d a y " , " S a t u r d a y " , " Sunday " } ;
8
9
f o r ( i n t i = 0 ; i < 7 ; i ++)
10
c o u t << weekDays [ i ] << e n d l ;
11
12
return 0;
13 }
8.6
Multi-Dimensional Arrays
C++ allows creation of arrays with 2 or more dimensions. Below is an example of declaring,
initializing and printing a 2-dimensional array of numbers.
Code 8.10: Example 2D Array
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o n s t i n t columns = 6 ;
6
c o n s t i n t rows = 4 ;
7
i n t my2DArray [ rows ] [ c o l u m n s ] ;
8
9
f o r ( i n t i = 0 ; i < rows ; i ++){
10
f o r ( i n t j = 0 ; j < c o l u m n s ; j ++)
11
my2DArray [ i ] [ j ] = i + j ;
12
}
13
14
f o r ( i n t i = 0 ; i < rows ; i ++){
15
f o r ( i n t j = 0 ; j < c o l u m n s ; j ++)
16
c o u t << my2DArray [ i ] [ j ] << " " ;
17
c o u t << e n d l ;
18
}
19
return 0;
20 }
Chapter 8. Arrays
110
Code 8.11: Another 2D Array Example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void p ri n t Ar r a y ( const i n t [ ] [ 3 ] ) ;
5 c o n s t i n t rows = 2 ;
6 c o n s t i n t columns = 3 ;
7
8 i n t main ( ) {
9
i n t a r r a y 1 [ rows ] [ c o l u m n s ] = { { 1 , 2 , 3 } , { 4 , 5 , 6 } } ;
10
i n t a r r a y 2 [ rows ] [ c o l u m n s ] = { 1 , 2 , 3 , 4 , 5 } ;
11
i n t a r r a y 3 [ rows ] [ c o l u m n s ] = { { 1 , 2 } , { 4 } } ;
12
13
c o u t << " V a l u e s i n a r r a y 1 a r e : " << e n d l ;
14
printArray ( array1 ) ;
15
16
c o u t << " V a l u e s i n a r r a y 2 a r e : " << e n d l ;
17
printArray ( array2 ) ;
18
19
c o u t << " V a l u e s i n a r r a y 3 a r e : " << e n d l ;
20
printArray ( array3 ) ;
21
22
return 0;
23 }
24
25 v o i d p r i n t A r r a y ( c o n s t i n t a [ ] [ c o l u m n s ] ) {
26
f o r ( i n t i = 0 ; i < rows ; i ++){
27
f o r ( i n t j = 0 ; j < c o l u m n s ; j ++)
28
c o u t << a [ i ] [ j ] << " " ;
29
c o u t << e n d l ;
30
}
31 }
<— Get code here.
8.7 Practice Questions
8.7
111
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) array index:
(b) array length / size:
2. True-False questions – Circle your choice
(a) The same array can store different types of values. ( True - False )
(b) The statement s[4] refers to the fourth element of array s. ( True - False )
(c) The statement array[5][6] reads the value of the array element in row 5 and column 6. (
True - False )
(d) In C++ all arrays are passed as arguments to a function by value. ( True - False )
(e) The elements of the same C++ array can be of different data types. ( True - False )
3. Fill in the blanks.
(a) The number used to refer to a specific element in an array is called its
.
(b) A 5 x 3 array contains
rows,
columns and
elements.
4. Given the array declaration, int a[20]; The first element of this array is written as:
(a)
(b)
(c)
(d)
(e)
a[1]
a[0]
a
a[19]
a[20]
Chapter 8. Arrays
112
5. Fix the errors in the code to obtain the desired output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void modifyArray ( i n t [ ] , i n t ) ;
5
6 i n t main ( ) {
7
8
const i n t arraySize = 5;
9
i n t myArray [ a r r a y S i z e ] = { 3 , 4 , 6 , 2 , 8 , 9 } ;
10
11
m o d i f y A r r a y ( myArray , a r r a y S i z e ) ;
12
13
return 0;
14 } / / end main
15
16 v o i d m o d i f y A r r a y ( c o n s t i n t a [ ] ) {
17
f o r ( i n t i = 0 ; i < s i z e O f A r r a y ; i ++){
18
a [ i ]++;
19
c o u t << a [ i ] << e n d l ;
20
}
21 }
Desired output:
4
5
7
3
9
10
8.7 Practice Questions
6. Fix the errors in the following code.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
c h a r weekDays [ ] = { " Monday " , " T u e s d a y " , " Wednesday " ,
7
" T h u r s d a y " , " F r i d a y " , " S a t u r d a y " , " Sunday " } ;
8
9
f o r ( i n t i = 0 ; i < 7 ; i ++){
10
c o u t << weekDays [ i ] << e n d l ;
11
}
12
return 0;
13 }
113
114
Chapter 8. Arrays
7. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void p ri n t Ar r a y ( const i n t [ ] [ 3 ] ) ;
5 c o n s t i n t rows = 2 ;
6 c o n s t i n t columns = 3 ;
7
8 i n t main ( ) {
9
i n t a r r a y 1 [ rows ] [ c o l u m n s ] = { { 1 , 2 , 3 } , { 4 , 5 , 6 } } ;
10
i n t a r r a y 2 [ rows ] [ c o l u m n s ] = { 1 , 2 , 3 , 4 , 5 } ;
11
i n t a r r a y 3 [ rows ] [ c o l u m n s ] = { { 1 , 2 } , { 4 } } ;
12
13
c o u t << " V a l u e s i n a r r a y 1 a r e : " << e n d l ;
14
printArray ( array1 ) ;
15
16
c o u t << " V a l u e s i n a r r a y 2 a r e : " << e n d l ;
17
printArray ( array2 ) ;
18
19
c o u t << " V a l u e s i n a r r a y 3 a r e : " << e n d l ;
20
printArray ( array3 ) ;
21
22
return 0;
23 }
24
25 v o i d p r i n t A r r a y ( c o n s t i n t a [ ] [ c o l u m n s ] ) {
26
f o r ( i n t i = 0 ; i < rows ; i ++){
27
f o r ( i n t j = 0 ; j < c o l u m n s ; j ++)
28
c o u t << a [ i ] [ j ] << " " ;
29
c o u t << e n d l ;
30
}
31 }
8.7 Practice Questions
8. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t myArray [ 6 ] = { 3 , 4 , 6 , 2 , 4 , 7 } ;
7
8
c o u t << s i z e o f ( myArray ) << e n d l ;
9
c o u t << s i z e o f ( myArray [ 0 ] ) << e n d l ;
10
11
return 0;
12 }
9. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o n s t i n t columns = 4 ;
6
c o n s t i n t rows = 3 ;
7
i n t my2DArray [ rows ] [ c o l u m n s ] ;
8
9
f o r ( i n t i = 0 ; i < rows ; i ++){
10
f o r ( i n t j = 0 ; j < c o l u m n s ; j ++)
11
my2DArray [ i ] [ j ] = 6− i + j ;
12
}
13
14
f o r ( i n t i = 0 ; i < rows ; i ++){
15
f o r ( i n t j = 0 ; j < c o l u m n s ; j ++)
16
c o u t << my2DArray [ i ] [ j ] << " " ;
17
c o u t << e n d l ;
18
}
19
return 0;
20 }
115
116
Chapter 8. Arrays
10. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t my2DArray [ 3 ] [ 3 ] = { { 1 , 2 , 3 } , { 4 , 5 , 6 } , { 7 , 8 , 9 } } ;
7
8
c o u t << my2DArray [ 1 ] [ 0 ] << e n d l ;
9
c o u t << my2DArray [ 2 ] [ 1 ] << e n d l ;
10
c o u t << my2DArray [ 1 ] [ 2 ] << e n d l ;
11
12
return 0;
13 }
8.7 Practice Questions
117
11. Make only one change to the program below so that the current output changes to the desired
output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
c h a r * weekDays [ 7 ] = { " Monday " , " T u e s d a y " ,
7
" Wednesday " , " T h u r s d a y " , " F r i d a y " , " S a t u r d a y " , " Sunday " } ;
8
9
f o r ( i n t i = 0 ; i < 7 ; i ++){
10
c o u t << weekDays [ i ] << e n d l ;
11
}
12
13
return 0;
14 }
Current output:
Monday
Tuesday
Wednesday
Thursday
Friday
Saturday
Sunday
Desired output:
M
T
W
T
F
S
S
Chapter 8. Arrays
118
12. Make only one change to the program below so that the current output changes to the desired
output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c h a r * weekDays [ 7 ] = { " Monday " , " T u e s d a y " ,
6
" Wednesday " , " T h u r s d a y " , " F r i d a y " , " S a t u r d a y " , " Sunday " } ;
7
8
f o r ( i n t i = 0 ; i < 7 ; i ++){
9
c o u t << weekDays [ 0 ] [ i ] << e n d l ;
10
}
11
12
return 0;
13 }
Current output:
M
o
n
d
a
y
Desired output:
Monday
onday
nday
day
ay
y
8.7 Practice Questions
119
13. Complete the program below so that it prints the content of My2Darray as shown in the
output column. Use a nested for loop to print the values. Use the tab feature to print the
values in distinct columns as shown.
1 ## i n c l u d e < i o s t r e a m >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o n s t i n t columns = 3 ;
6
c o n s t i n t rows = 4 ;
7
i n t my2DArray [ rows ] [ c o l u m n s ] = { 1 , 2 , 3 , 4 , 5 , 6 , 7 , 8 , 9 , 1 0 , 1 1 , 1 2 } ;
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
return 0;
25 }
Desired output:
1
4
7
10
2
5
8
11
3
6
9
12
Chapter 8. Arrays
120
14. Assume we want to store 5 double data values for further processing (example find their
average). Write a program that allows the user to input 5 numerical values and uses an array
to store the data values and calculate the average of all these values.
Desired output:
Enter value:
5
6
8
2.3
3.2
The Average is: 4.9
15. Write a function definition LinearSearch(. . . .) to perform a linear search of an array. The
function should receive an integer array and the size of the array as arguments, and the key.
If the search key is found, return the array index; otherwise, return -1. Make sure you use the
proper function return type and argument list. Just write the function definition. You do not
need to write a complete C++ program.
16. Write the function void rotateRight (int n, char a[]) which moves each of the n characters
one position to the right, but moves the last character to the first position. For example, if
a contained n = 4 characters, ABCD, then when the function is finished, it would contain
DABC. Make sure you use the proper function return type and argument list. Just write the
function definition. You do not need to write a complete C++ program.
17. Write a function definition largestIndex(. . . ) that returns the index of the largest element
of a global integer array myArray of length 100. Make sure you use the proper function
return type and argument list. Just write the function definition. You do not need to write a
complete C++ program.
18. Write a function averageValue(. . . ) that returns the average of all the elements in a global
array myArray of double values. (hint: the number of elements in array a must be passed
to the function.) Make sure you use the proper function return type and argument list. Just
write the function definition. You do not need to write a complete C++ program.
9. Pointers
9.1
What are Pointers?
Pointers are a powerful feature of C++. They allow the user to pass-by-reference which in turn
allows manipulation of more complex, dynamic data structures. Pointers will be extensively used
in later more advanced topics.
Code 9.1: Pointers first example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t x = 5;
7
i n t * x P o i n t e r = &x ;
8
9
c o u t << " A d d r e s s o f x : " << &x << e n d l ;
10
c o u t << " V a l u e o f x P o i n t e r : " << x P o i n t e r << e n d l << e n d l ;
11
12
c o u t << " A d d r e s s o f x P o i n t e r : " << &x P o i n t e r << e n d l << e n d l ;
13
14
c o u t << " V a l u e o f x : " << x << e n d l ;
15
c o u t << " V a l u e o f * x P o i n t e r : " << * x P o i n t e r << e n d l ;
16
17
return 0;
18 }
<— Get code here.
Chapter 9. Pointers
122
Code 9.2: Another example using pointers
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void doubleValue ( i n t *p ) ;
5
6 i n t main ( ) {
7
8
i n t myInt = 5 ;
9
c o u t << " m y I n t b e f o r e d o u b l i n g : " << m y I n t << e n d l ;
10
d o u b l e V a l u e (& m y I n t ) ;
11
c o u t << " m y I n t a f t e r d o u b l i n g : " << m y I n t << e n d l ;
12
13
return 0;
14 } / / end main ( )
15
16 v o i d d o u b l e V a l u e ( i n t * p ) {
17
*p = *p * 2 ;
18 } / / end d o u b l e V a l u e ( )
Write a C++ program that swaps the values of two integer variables a and b. Use a
function swap1(*p1, *p2). Print a and b before and after swapping. Your output should
have the same format and should work for any integer a user enters. Use pointers.
Desired output format:
The value of a before swapping is: 4
The value of b before swapping is: 7
The value of a after swapping is: 7
The value of b after swapping is: 4
9.2
Arrays and Pointer Arithmetic
Arrays store values in consecutive memory locations. Pointer can be very useful when processing
arrays. The example below illustrates some of the array properties and the use of pointers.
9.2 Arrays and Pointer Arithmetic
123
Code 9.3: Arrays and pointers example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
const i n t arraySize = 5;
7
i n t myArray [ a r r a y S i z e ] = { 2 , 4 , 7 , 9 , 1 } ;
8
i n t * p = myArray ;
9
10
c o u t << " I n d e x \ t V a l u e \ t A d d r e s s " << e n d l << e n d l ;
11
12
f o r ( i n t i = 0 ; i < a r r a y S i z e ; i ++){
13
c o u t << i << " \ t " ;
14
c o u t << myArray [ i ] << " \ t " ;
15
c o u t << &myArray [ i ] << " \ t " << e n d l ;
16
}
17
c o u t << e n d l ;
18
19
c o u t << " p i s p o i n t i n g a t a d d r e s s : " << p << e n d l ;
20
c o u t << " The v a l u e o f * p i s : " << * p << e n d l << e n d l ;
21
22
c o u t << " Moving p t o t h e n e x t memory a d d r e s s . " << e n d l ;
23
p = p +1;
24
25
c o u t << " p i s p o i n t i n g a t a d d r e s s : " << p << e n d l ;
26
c o u t << " The v a l u e o f * p i s : " << * p << e n d l ;
27
28
return 0;
29 }
<— Get code here.
Change myArray from an array of integers to a double array. Run the program, compare
any two consecutive addresses. What do you notice?
Change line 8 from int *p = myArray; to int *p = &myArray[0]. Is there any difference
in the output? Why?
Chapter 9. Pointers
124
Code 9.4: Using pointers to work with strings
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4
5 c h a r * m y S t r i n g s [ 4 ] = { " one " , " two " , " t h r e e " , " f o u r " } ;
6
7 i n t main ( ) {
8
9
c o u t << " P r i n t i n g t h e a r r a y c o n t e n t . " << e n d l ;
10
f o r ( i n t i = 0 ; i < 4 ; i ++)
11
c o u t << m y S t r i n g s [ i ] << e n d l ;
12
c o u t << e n d l ;
13
14
c o u t << " P r i n t i n g t h e a d d r e s s o f e a c h s t r i n g . " << e n d l ;
15
f o r ( i n t i = 0 ; i < 4 ; i ++)
16
c o u t << &m y S t r i n g s [ i ] << e n d l ;
17
c o u t << e n d l ;
18
19
c o u t << " P r i n t i n g s u b s t r i n g s o f t h e t h i r d s t r i n g . " << e n d l ;
20
f o r ( i n t i = 0 ; i < 5 ; i ++)
21
c o u t << &m y S t r i n g s [ 2 ] [ i ] << e n d l ;
22
c o u t << e n d l ;
23
24
c o u t << " P r i n t i n g t h e v a l u e where p o i n t e r s a r e . " << e n d l ;
25
f o r ( i n t i = 0 ; i < 4 ; i ++)
26
c o u t << * m y S t r i n g s [ i ] << e n d l ;
27
c o u t << e n d l ;
28
29
return 0;
30 }
<— Get code here.
10. Structures
10.1
What are Structures?
We have used variables that allow us to store information in the computer. Variable types such
as int, char, etc. allow us to save information of a single type. Structures allow us to organize
information as collections of values that belong to the same entity and are connected to one another
in a meaningful way. Understanding structures is a helpful step to better understand classes and
objects which we will discuss in the next chapter.
Code 10.1: Structure example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 s t r u c t Course {
5
i n t courseNumber ;
6
char grade ;
7 };
8
9 i n t main ( ) {
10
11
C o u r s e myCourse ;
12
myCourse . c o u r s e N u m b e r = 1 0 1 ;
13
myCourse . g r a d e = ’A ’ ;
14
15
c o u t << " I t o o k MAC " << myCourse . c o u r s e N u m b e r ;
16
c o u t << " and I g o t a ( n ) " << myCourse . g r a d e << e n d l ;
17
18
return 0;
19 }
126
Chapter 10. Structures
Add a new structure to the program above named Exam, which has two member variables,
examNumber and grade. Assign values from main() to both variables, then print the
results similar to what we did with the Course structure. Is it working? Is there a problem
using the same name (grade) for both structures?
Code 10.2: Alternative way of initializing structures
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 s t r u c t Course {
5
i n t courseNumber ;
6
char grade ;
7 };
8
9 i n t main ( ) {
10
11
C o u r s e myCourse = { 1 0 1 , ’A ’ } ;
12
13
c o u t << " I t o o k MAC " << myCourse . c o u r s e N u m b e r ;
14
c o u t << " and I g o t a ( n ) " << myCourse . g r a d e << e n d l ;
15
16
return 0;
17 }
Swap the values 101 and ’A’. Does it work? What do you notice?
10.2 Structure Composition
10.2
127
Structure Composition
It is possible to have a structure be a member of another structure.
Code 10.3: Structure composition example
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 s t r u c t Course {
6
i n t courseNumber ;
7
char grade ;
8 };
9
10 s t r u c t S t u d e n t {
11
s t r i n g studentName ;
12
Course s t u d e n t C o u r s e ;
13 } ;
14
15 i n t main ( ) {
16
17
Student st1 ;
18
s t 1 . s t u d e n t N a m e = " Bob " ;
19
s t 1 . s t u d e n t C o u r s e . courseNumber = 101;
20
s t 1 . s t u d e n t C o u r s e . g r a d e = ’A ’ ;
21
22
c o u t << s t 1 . s t u d e n t N a m e ;
23
c o u t << " t o o k MAC " << s t 1 . s t u d e n t C o u r s e . c o u r s e N u m b e r ;
24
c o u t << " and g o t a ( n ) " << s t 1 . s t u d e n t C o u r s e . g r a d e << e n d l ;
25
26
return 0;
27 }
<— Get code here.
Chapter 10. Structures
128
10.3
Arrays of Structures
Multiple structures of the same type can be stored using an array.
Code 10.4: Example storing structures in an array
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 s t r u c t Course {
5
i n t courseNumber ;
6
char grade ;
7 };
8
9 i n t main ( ) {
10
c o n s t i n t numberOfCourses = 4 ;
11
Course c o u r s e L i s t [ numberOfCourses ] = {
12
{ 1 0 1 , ’A ’ } ,
13
{ 1 2 5 , ’B ’ } ,
14
{ 1 9 0 , ’C ’ } ,
15
{ 2 8 6 , ’A ’ }
16
};
17
18
c o u t << " C o u r s e l i s t : " << e n d l ;
19
f o r ( i n t i = 0 ; i < n u m b e r O f C o u r s e s ; i ++){
20
c o u t << c o u r s e L i s t [ i ] . c o u r s e N u m b e r ;
21
c o u t << " " << c o u r s e L i s t [ i ] . g r a d e << e n d l ;
22
}
23
24
return 0;
25 }
<— Get code here.
What are the similarities and differences between structures and arrays?
10.4 Passing Structures to Functions
10.4
129
Passing Structures to Functions
Structures can also serve as arguments for function parameters, much like any primitive data types.
By default structures are passed by value.
Code 10.5: Passing a structure to function example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 s t r u c t Course {
5
i n t courseNumber ;
6
char grade ;
7 };
8
9 void p r i n t C o u r s e ( Course ) ;
10
11 i n t main ( ) {
12
c o n s t i n t numberOfCourses = 4 ;
13
Course c o u r s e L i s t [ numberOfCourses ] = {
14
{ 1 0 1 , ’A ’ } ,
15
{ 1 2 5 , ’B ’ } ,
16
{ 1 9 0 , ’C ’ } ,
17
{ 2 8 6 , ’A ’ }
18
};
19
20
c o u t << " C o u r s e l i s t : " << e n d l ;
21
f o r ( i n t i = 0 ; i < n u m b e r O f C o u r s e s ; i ++)
22
printCourse ( courseList [ i ] ) ;
23
24
return 0;
25 }
26
27 v o i d p r i n t C o u r s e ( C o u r s e c ) {
28
c o u t << c . c o u r s e N u m b e r ;
29
c o u t << " " << c . g r a d e << e n d l ;
30 }
1. Change the previous program to pass each structure to the function by reference.
The program should produce the same output.
2. Similarly change the program to give the function a pointer to each structure.
11. Introduction to Classes
11.1
Objects
C++ is an object-oriented programming language that provides a powerful paradigm for developing
software applications. With its support for OOP, C++ enables programmers to create custom data
types that closely mirror real-life scenarios, making the code more intuitive, organized, and reusable.
This approach to programming results in software that is easy to understand, maintain, and extend,
and ultimately results in higher-quality applications.
What is an object?
What sets two objects apart?
Do different objects have anything in common?
Chapter 11. Introduction to Classes
132
11.2
Classes
Until now for the most part we have used primitive data types such as int or char to process
information. Following the OOP principles, a programmer can specify his/her own type based on
what objects he/she intends to work with.
To enable creation of such objects a programmer needs to identify common characteristics and
behavior of these objects and create a class using this information.
A class is a blueprint (template) which is used when we create an object. A class describes
collectively characteristics and behavior of the same type of objects.
We can create multiple objects from the same class. Each object is unique but they all share common
features of all other objects derived from the same class.
An object created from a class is referred to as an instance of the class. The process of creating an
object is called instantiation.
11.3
The First Example
Code 11.1: First example of a class
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 class Rectangle {
5 public :
6
i n t width , l e n g t h ;
7 } ; / / end R e c t a n g l e c l a s s
8
9 i n t main ( ) {
10
Rectangle r1 ;
11
r1 . width =3;
12
r1 . l e n g t h =5;
13
c o u t << " r 1 i s a " << r 1 . w i d t h ;
14
c o u t << " x " << r 1 . l e n g t h << " r e c t a n g l e . " << e n d l ;
15
16
return 0;
17 } / / end main ( )
Remove the public keyword and run the program. What do you notice?
What happens if we do not initialize class members?
11.3 The First Example
133
Code 11.2: Adding class member functions
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 class Rectangle {
5 public :
6
i n t width , l e n g t h ;
7
void printArea ( ) {
8
c o u t << " Area = " << w i d t h * l e n g t h << e n d l ;
9
}
10 } ; / / end R e c t a n g l e c l a s s
11
12 i n t main ( ) {
13
Rectangle r1 ;
14
r1 . width =3;
15
r1 . l e n g t h =5;
16
r1 . printArea ( ) ;
17
return 0;
18 } / / end main ( )
Code 11.3: Access specifiers, data hiding and encapsulation
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 class Rectangle {
5 private :
6
i n t width , l e n g t h ;
7 public :
8
v o i d s e t ( i n t w, i n t l ) { w i d t h = w ; l e n g t h = l ; }
9
i n t getWidth ( ) { r e t u r n width ;}
10
i n t getLength ( ) { return length ;}
11
12
void printArea ( ) {
13
c o u t << " Area = " << w i d t h * l e n g t h << e n d l ;
14
}
15 } ; / / end R e c t a n g l e c l a s s
16
17 i n t main ( ) {
18
Rectangle r1 ;
19
r1 . s e t ( 4 , 7 ) ;
20
c o u t << " D i m e n s i o n s : " << r 1 . g e t W i d t h ( ) ;
21
c o u t << " x " << r 1 . g e t L e n g t h ( ) << e n d l ;
22
r1 . printArea ( ) ;
23
return 0;
24 }
12. Strings
12.1
How C++ Stores Text?
All information in the computer is stored using 0s and 1s. Therefore, all data is stored as a number.
When it comes to text, each character is stored using the corresponding ASCII number. Each
character gets one byte of memory space.
How many different characters can be represented with one byte of memory space?
Chapter 12. Strings
136
Code 12.1: Example displaying the ASCII value of a char variable.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
# include <iostream >
# include <bitset >
# i n c l u d e <iomanip >
u s i n g namespace s t d ;
i n t main ( )
{
char c ;
c o u t << " E n t e r any c h a r a c t e r : " ;
c i n >> c ;
c o u t << " The c h a r a c t e r you e n t e r e d i s : " << c << e n d l ;
c o u t << " I t s ASCII c o d e ( d e c i m a l ) i s : " << ( i n t ) c << e n d l ;
b i t s e t <8> x ( c ) ;
c o u t << " I t s ASCII c o d e ( b i n a r y ) i s : " << x << e n d l ;
c o u t << " I t s ASCII c o d e ( h e x a d e c i m a l ) i s : " ;
c o u t << s e t w ( 2 ) << s e t f i l l ( ’ 0 ’ ) << hex << ( i n t ) c << e n d l ;
return 0;
}
Code 12.2: Example converting ascii value to char.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
# include <iostream >
# include <bitset >
# i n c l u d e <iomanip >
u s i n g namespace s t d ;
i n t main ( ) {
int ascii ;
c o u t << " E n t e r an i n t e g e r b e t w e e n 0 and 2 5 5 : " ;
c i n >> a s c i i ;
c o u t << " The i n t e g e r you e n t e r e d i s : " << a s c i i << e n d l ;
c o u t << " The ASCII c h a r a c t e r i s : " << ( c h a r ) a s c i i << e n d l ;
return 0;
}
12.2 C-style String Functions
137
Write a program that uses a for loop to print all the ASCII characters and their corresponding decimal values in tabular format. See the sample output for some of the characters
below:
Desired output format:
...
...
35 #
36 $
37 %
...
...
12.2
C-style String Functions
C++ has a number of pre-defined functions inherited from C that help the programmer manipulate
arrays of characters or strings. The example below illustrates some of these functions.
Code 12.3: Example using cstring functions.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
char s [ 8 0 ] ;
6
s t r c p y ( s , " One " ) ;
7
s t r c a t ( s , "Two" ) ;
8
s t r c a t ( s , " Three " ) ;
9
c o u t << " The s t r i n g c r e a t e d i s : " << s << e n d l ;
10
c o u t << " The l e n g t h o f t h e s t r i n g i s : " << s t r l e n ( s ) ;
11
12
return 0;
13 }
There is something missing in the above program which may prevent the program from
running. Can you fix it?
Chapter 12. Strings
138
Code 12.4: Reading string input example.
1 # include <iostream >
2 # include <cstring >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
char s [ 8 0 ] ;
7
c o u t << " E n t e r s t r i n g : " ;
8
c i n >> s ;
9
c o u t << " The s t r i n g e n t e r e d i s : " << s << e n d l ;
10
c o u t << " The l e n g t h o f t h e s t r i n g i s : " << s t r l e n ( s ) ;
11
12
return 0;
13 }
Enter a string consisting of more than one word. Does it work?
Substitute the line cin » s; with the line cin.getline(s,79); Run the program and input the
string “Hello World”. What changed?
Now input a long string of more than 80 characters. What do you notice?
12.3
The <string> Class
The <string> class makes it easier for programmers to manipulate strings. A string derived from
this class is an object, but it has similarities to primitive data types such as int or char. We will
discuss classes and objects in more detail in the upcoming chapters.
12.3 The <string> Class
139
Code 12.5: Different ways to initialize a string object.
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
7
s t r i n g myString1 ;
8
s t r i n g m y S t r i n g 2 = " H e l l o MAC101 c l a s s ! " ;
9
s t r i n g myString3 ( " Using P a r e n t h e s i s " ) ;
10
s t r i n g myString4 ( myString3 ) ;
11
s t r i n g myString5 ( myString2 , 6 ) ;
12
s t r i n g myString6 ( myString2 , 6 , 6 ) ;
13
14
c o u t << " 1 : " << m y S t r i n g 1 << e n d l ;
15
c o u t << " 2 : " << m y S t r i n g 2 << e n d l ;
16
c o u t << " 3 : " << m y S t r i n g 3 << e n d l ;
17
c o u t << " 4 : " << m y S t r i n g 4 << e n d l ;
18
c o u t << " 5 : " << m y S t r i n g 5 << e n d l ;
19
c o u t << " 6 : " << m y S t r i n g 6 << e n d l ;
20
21
return 0;
22 }
Code 12.6: String input and concatenation example.
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
s t r i n g s t r , name , a d d r ;
7
8
c o u t << " E n t e r name : " ;
9
g e t l i n e ( c i n , name ) ;
10
c o u t << " E n t e r a d d r e s s : " ;
11
g e t l i n e ( cin , addr ) ;
12
13
s t r = "My name i s " + name + " . " + " I l i v e i n " + a d d r + " . " ;
14
c o u t << s t r << e n d l ;
15
16
return 0;
17 }
Chapter 12. Strings
140
Code 12.7: Comparing strings example.
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
7
s t r i n g s t r i n g 1 = " one " ;
8
s t r i n g s t r i n g 2 ( " one " ) ;
9
string string3 ( " five " );
10
s t r i n g string4 ( " ten " ) ;
11
12
i f ( s t r i n g 1 == s t r i n g 2 )
13
c o u t << " The s t r i n g s a r e t h e same " << e n d l ;
14
else
15
c o u t << " The s t r i n g s a r e d i f f e r e n t " << e n d l ;
16
17
i f ( ! s t r i n g 1 . compare ( s t r i n g 2 ) )
18
c o u t << " The s t r i n g s a r e t h e same " << e n d l ;
19
else
20
c o u t << " The s t r i n g s a r e d i f f e r e n t " << e n d l ;
21
c o u t << s t r i n g 1 . compare ( s t r i n g 2 ) ;
22
23
return 0;
24 }
12.3 The <string> Class
141
Code 12.8: Working with strings additional example.
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
7
s t r i n g c i t y = "New" ;
8
c o u t << " I n i t i a l s t r i n g : " << c i t y << e n d l ;
9
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c i t y . append ( " c i t y ! " ) ;
11
c o u t << " A f t e r a p p e n d i n g : " << c i t y << e n d l ;
12
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c i t y [ 4 ] = ’C ’ ;
14
c o u t << " A f t e r c h a r c h a n g e : " << c i t y << e n d l ;
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s t r i n g s 2 = " York " ;
17
c i t y . i n s e r t ( 4 , s2 ) ;
18
c o u t << " A f t e r i n s e r t : " << c i t y << e n d l ;
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city . erase (8 , 5);
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c o u t << " A f t e r e r a s e : " << c i t y << e n d l ;
22
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f o r ( i n t i = 0 ; i < c i t y . s i z e ( ) ; i ++){
24
f o r ( i n t j = 0 ; j < i ; j ++)
25
c o u t << " " ;
26
c o u t << c i t y [ i ] << e n d l ;
27
}
28
return 0;
29 }
Write a C++ program that takes a string as an input and prints the string in reverse order.
Use a loop for this program, do not use any built-in function to reverse the string.
Desired output format:
Enter a string: Hello World
The string you entered in reverse order is: dlroW olleH
Chapter 12. Strings
142
Write a C++ program that takes as an input two strings from the user and determines
whether the first string is a substring of the second. If yes, also print at what position the
substring starts.
Desired output format 1:
Enter first string: Hello World
Enter second string: World
"World" is a substring of "Hello World".
It starts at position 6
Desired output format 2:
Enter first string: Hello World
Enter second string: apple
"apple" is NOT a substring of "Hello World".
13. Basic Sorting Algorithms
13.1
Sorting Algorithms
Very often we need to arrange (sort) data for searching or other purposes. There is a large variety of
sorting algorithms. We will only discuss here the simplest algorithms.
Chapter 13. Basic Sorting Algorithms
144
Code 13.1: Bubble Sort example.
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# include <iostream >
# i n c l u d e <iomanip >
u s i n g namespace s t d ;
i n t myArray [ ] = { 7 , 2 , 4 , 2 , 9 , 5 , 6 , 1 , 5 } ;
i n t a r r a y S i z e = s i z e o f ( myArray ) / s i z e o f ( myArray [ 0 ] ) ;
void BubbleSort ( ) ;
v o i d swap ( i n t one , i n t two ) ;
void printMyArray ( int , i n t ) ;
i n t main ( ) {
c o u t << " A r r a y v a l u e s b e f o r e s o r t i n g : " << e n d l ;
printMyArray ( −1 , −1);
BubbleSort ( ) ;
c o u t << " \ nThe a r r a y h a s b e e n s o r t e d . " ;
return 0;
} / / end main
void BubbleSort ( ) {
f o r ( i n t i = 0 ; i < a r r a y S i z e ; i ++)
f o r ( i n t j = 0 ; j < a r r a y S i z e −1− i ; j ++){
i f ( myArray [ j ] > myArray [ j + 1 ] )
swap ( j , j + 1 ) ;
}
} / / end B u b b l e S o r t
v o i d swap ( i n t one , i n t two ) {
i n t temp = myArray [ one ] ;
myArray [ one ] = myArray [ two ] ;
myArray [ two ] = temp ;
s t a t i c i n t swapCount = 1 ;
c o u t << " Swap " << s e t w ( 2 ) << swapCount ++ << " :
p r i n t M y A r r a y ( one , two ) ;
} / / end swap
v o i d p r i n t M y A r r a y ( i n t one , i n t two ) {
f o r ( i n t j = 0 ; j < a r r a y S i z e ; j ++)
i f ( j == one o r j ==two )
c o u t << " ( " << myArray [ j ] << " ) " ;
else
c o u t << " " << myArray [ j ] << " " ;
c o u t << e n d l ;
} / / end p r i n t M y A r r a y ( )
<— Get code here.
";
13.1 Sorting Algorithms
145
Code 13.2: Selection sort example.
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# include <iostream >
# i n c l u d e <iomanip >
u s i n g namespace s t d ;
i n t myArray [ ] = { 7 , 2 , 4 , 2 , 9 , 5 , 6 , 1 , 5 } ;
i n t a r r a y S i z e = s i z e o f ( myArray ) / s i z e o f ( myArray [ 0 ] ) ;
void S e l e c t i o n S o r t ( ) ;
v o i d swap ( i n t one , i n t two ) ;
void printMyArray ( int , i n t ) ;
i n t main ( ) {
c o u t << " A r r a y v a l u e s b e f o r e s o r t i n g : " << e n d l ;
printMyArray ( −1 , −1);
SelectionSort ();
c o u t << " \ nThe a r r a y h a s b e e n s o r t e d . " ;
return 0;
} / / end main
void S e l e c t i o n S o r t ( ) {
i n t min ;
f o r ( i n t i = 0 ; i < a r r a y S i z e − 1 ; i ++){
min= i ;
f o r ( i n t j = i + 1 ; j < a r r a y S i z e ; j ++)
i f ( myArray [ j ] < myArray [ min ] ) min= j ;
swap ( i , min ) ;
}
} / / end S e l e c t i o n S o r t
v o i d swap ( i n t one , i n t two ) {
i n t temp = myArray [ one ] ;
myArray [ one ] = myArray [ two ] ;
myArray [ two ] = temp ;
s t a t i c i n t swapCount = 1 ;
c o u t << " Swap " << s e t w ( 2 ) << swapCount ++ << " :
p r i n t M y A r r a y ( one , two ) ;
} / / end swap
v o i d p r i n t M y A r r a y ( i n t one , i n t two ) {
f o r ( i n t j = 0 ; j < a r r a y S i z e ; j ++)
i f ( j == one o r j ==two )
c o u t << " ( " << myArray [ j ] << " ) " ;
else
c o u t << " " << myArray [ j ] << " " ;
c o u t << e n d l ;
} / / end p r i n t M y A r r a y ( )
<— Get code here.
";
Chapter 13. Basic Sorting Algorithms
146
Code 13.3: Insertion sort example.
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# include <iostream >
u s i n g namespace s t d ;
i n t myArray [ ] = { 7 , 2 , 4 , 2 , 9 , 5 , 6 , 1 , 5 } ;
i n t a r r a y S i z e = s i z e o f ( myArray ) / s i z e o f ( myArray [ 0 ] ) ;
void I n s e r t i o n S o r t ( ) ;
void printMyArray ( int , i n t ) ;
i n t main ( ) {
c o u t << " A r r a y v a l u e s b e f o r e s o r t i n g : " << e n d l ;
printMyArray ( −1 , −1);
InsertionSort ();
c o u t << " \ nThe a r r a y h a s b e e n s o r t e d . " ;
return 0;
} / / end main ( )
void I n s e r t i o n S o r t ( ) {
i n t h e r e , n e x t , temp ;
printMyArray ( −1 , 1 ) ;
f o r ( n e x t = 1 ; n e x t < a r r a y S i z e ; n e x t ++){
temp=myArray [ n e x t ] ;
here = next ;
w h i l e ( h e r e >0 && myArray [ h e r e −1] >= temp ) {
myArray [ h e r e ] = myArray [ h e r e − 1 ] ;
h e r e − −;
}
myArray [ h e r e ] = temp ;
printMyArray ( here , next +1);
} / / end f o r
} / / end I n s e r t i o n S o r t ( )
void printMyArray ( i n t i n s e r t e d , i n t nextValue ) {
f o r ( i n t j = 0 ; j < a r r a y S i z e ; j ++){
i f ( j == n e x t V a l u e )
c o u t << " <−− S o r t e d | U n s o r t e d −−> " ;
i f ( j == i n s e r t e d )
c o u t << " ( " << myArray [ j ] << " ) " ;
else
c o u t << " " << myArray [ j ] << " " ;
}
c o u t << e n d l ;
} / / end p r i n t M y A r r a y ( )
<— Get code here.
II
Part Two - MAC 125
14
Classes and Objects (continued...) . . 149
15
Classes, Pointers, and Arrays . . . . . . . . 159
16
Recursion . . . . . . . . . . . . . . . . . . . . . . . . . . 165
17
Inheritance . . . . . . . . . . . . . . . . . . . . . . . . 177
18
Polymorphism . . . . . . . . . . . . . . . . . . . . . . 187
19
Templates . . . . . . . . . . . . . . . . . . . . . . . . . . 193
20
Linked Data Structures . . . . . . . . . . . . . . 199
21
Exception Handling . . . . . . . . . . . . . . . . . 205
22
Standard Template Library . . . . . . . . . . 211
150
Chapter 14. Classes and Objects (continued...)
14. Classes and Objects (continued...)
14.1
Constructors
Code 14.1: Adding constructors
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 class Rectangle {
5 private :
6
i n t width , l e n g t h ;
7 public :
8
Rectangle () {
9
width =1; l e n g t h =2;
10
c o u t << " H e l l o w o r l d ! ! ! " << e n d l ;
11
}
12
v o i d s e t ( i n t w, i n t l ) { w i d t h = w ; l e n g t h = l ; }
13
i n t getWidth ( ) { r e t u r n width ;}
14
i n t getLength ( ) { return length ;}
15
16
void printArea ( ) {
17
c o u t << " Area = " << w i d t h * l e n g t h << e n d l ;
18
}
19 } ; / / end R e c t a n g l e c l a s s
20
21 i n t main ( ) {
22
Rectangle r1 ;
23
r1 . printArea ( ) ;
24
return 0;
25 }
14.1 Constructors
151
Add another constructor that takes two parameters and assigns those values to width and
length.
What can we conclude regarding constructor overloading in C++?
Can we call the constructor explicitly, say: r1.Rectangle(3,5);
Always include a default constructor.
152
14.2
Chapter 14. Classes and Objects (continued...)
Destructors
Code 14.2: Adding destructors
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 class Rectangle {
5 private :
6
i n t width , l e n g t h ;
7 public :
8
Rectangle () {
9
width =1; l e n g t h =2;
10
c o u t << " H e l l o w o r l d ! ! ! " << e n d l ;
11
}
12
~Rectangle (){
13
c o u t << " Goodbye e v e r y o n e ! ! ! " << e n d l ;
14
}
15
v o i d s e t ( i n t w, i n t l ) { w i d t h = w ; l e n g t h = l ; }
16
i n t getWidth ( ) { r e t u r n width ;}
17
i n t getLength ( ) { return length ;}
18
19
void printArea ( ) {
20
c o u t << " Area = " << w i d t h * l e n g t h << e n d l ;
21
}
22 } ; / / end R e c t a n g l e c l a s s
23
24 i n t main ( ) {
25
Rectangle r1 ;
26
r1 . printArea ( ) ;
27
return 0;
28 }
14.3 Separating Content in Different Files
14.3
153
Separating Content in Different Files
It is common practice to separate the declaration and definition of each class into separate files.
First comes the header file ClassName.h then the source / implementation file ClassName.cpp.
Next, we create separate files to achieve the results from the previous example.
Code 14.3: Rectangle.h
1 # i f n d e f RECTANGLE_H_
2 # d e f i n e RECTANGLE_H_
3
4 class Rectangle {
5 private :
6
i n t width , l e n g t h ;
7 protected :
8 public :
9
Rectangle ( ) ;
10
R e c t a n g l e ( i n t w, i n t l ) ;
11
~Rectangle ( ) ;
12
void setWidth ( i n t ) ;
13
void setLength ( i n t ) ;
14
i n t getWidth ( ) ;
15
i n t getLength ( ) ;
16
void printArea ( ) ;
17 } ;
18
19 # e n d i f / * RECTANGLE_H_ * /
Chapter 14. Classes and Objects (continued...)
154
Code 14.4: Rectangle.cpp
1 # include " Rectangle . h"
2 # include <iostream >
3 u s i n g namespace s t d ;
4
5 Rectangle : : Rectangle ( ) { width = 1; l e n g t h = 2;}
6
7 R e c t a n g l e : : R e c t a n g l e ( i n t w, i n t l ) { w i d t h = w ; l e n g t h = l ; }
8
9 Rectangle ::~ Rectangle (){}
10
11 v o i d R e c t a n g l e : : s e t W i d t h ( i n t w) { w i d t h = w; }
12
13 v o i d R e c t a n g l e : : s e t L e n g t h ( i n t l ) { l e n g t h = l ; }
14
15 i n t R e c t a n g l e : : g e t W i d t h ( ) { r e t u r n w i d t h ; }
16
17 i n t R e c t a n g l e : : g e t L e n g t h ( ) { r e t u r n l e n g t h ; }
18
19 v o i d R e c t a n g l e : : p r i n t A r e a ( ) { c o u t << " Area = " << w i d t h * l e n g t h ; }
Code 14.5: Main program
1 # include " Rectangle . h"
2 # include <iostream >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
Rectangle r1 ;
7
r1 . printArea ( ) ;
8
return 0;
9 }
Write a class named Person that has data members name and age. Include a default and a
parameterized constructor, a destructor and a public member function named sayHello()
that that prints “Hello! I am “, followed by the name of the person on the screen.
14.4 Constant Objects
14.4
155
Constant Objects
Similar to primitive data types we can set objects as constant to prevent any changes to the object
during the execution of a program.
Code 14.6: Rectangle class example
1 # include <iostream >
2 u s i n g namespace s t d ;
3 / * *********** D e c l a r a t i o n S e c t i o n ***************** * /
4 class Rectangle {
5 private :
6
i n t width , l e n g t h ;
7 public :
8
Rectangle ( ) ;
9
R e c t a n g l e ( i n t w, i n t l ) ;
10
~Rectangle ( ) ;
11
void setWidth ( i n t ) ;
12
void setLength ( i n t ) ;
13
i n t getWidth ( ) ;
14
i n t getLength ( ) ;
15
void printArea ( ) ;
16 } ;
17 / * *********** I m p l e m e n t a t i o n S e c t i o n ***************** * /
18 R e c t a n g l e : : R e c t a n g l e ( ) { w i d t h = 1 ; l e n g t h = 2 ; }
19 R e c t a n g l e : : R e c t a n g l e ( i n t w, i n t l ) { w i d t h = w ; l e n g t h = l ; }
20 R e c t a n g l e : : ~ R e c t a n g l e ( ) { }
21 v o i d R e c t a n g l e : : s e t W i d t h ( i n t w) { w i d t h = w; }
22 v o i d R e c t a n g l e : : s e t L e n g t h ( i n t l ) { l e n g t h = l ; }
23 i n t R e c t a n g l e : : g e t W i d t h ( ) { r e t u r n w i d t h ; }
24 i n t R e c t a n g l e : : g e t L e n g t h ( ) { r e t u r n l e n g t h ; }
25 v o i d R e c t a n g l e : : p r i n t A r e a ( ) { c o u t << " Area = " << w i d t h * l e n g t h ; }
26 / * **************** Main S e c t i o n ******************** * /
27 i n t main ( ) {
28
Rectangle r1 ;
29
r1 . printArea ( ) ;
30
return 0;
31 }
<— Get code here.
Consider the example above. Make the following changes and run the program.
1. Declare Rectangle r1 as constant. What do you observe?
2. Change the printArea() function to constant.
3. Change the Rectangle r1 back to non-constant. What can you conclude?
Chapter 14. Classes and Objects (continued...)
156
14.5
Member Initializers
C++ offers an alternative syntax for initializing member variable via the constructor. Below is an
example using both alternatives. Consider the program below:
Code 14.7: Class example.
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# include <iostream >
u s i n g namespace s t d ;
/ * *********** D e c l a r a t i o n S e c t i o n ***************** * /
class Rectangle {
private :
i n t width , l e n g t h ;
public :
Rectangle ( ) ;
R e c t a n g l e ( i n t w, i n t l ) ;
void printArea ( ) ;
};
/ * *********** I m p l e m e n t a t i o n S e c t i o n ***************** * /
Rectangle : : Rectangle (){
width = 1 , l e n g t h = 2;
c o u t << " H e l l o t h e r e ! My i d i s " << t h i s << e n d l ;
}
R e c t a n g l e : : R e c t a n g l e ( i n t w, i n t l ) {
w i d t h = w, l e n g t h = l ;
c o u t << " H e l l o t h e r e ! My i d i s " << t h i s << e n d l ;
}
void Rectangle : : printArea ( ) {
c o u t << " Area o f " << t h i s << " = " << w i d t h * l e n g t h << e n d l ;
}
/ * **************** Main S e c t i o n ******************** * /
i n t main ( ) {
R e c t a n g l e r1 , r 2 ( 5 , 7 ) ;
r1 . printArea ( ) ;
r2 . printArea ( ) ;
return 0;
}
<— Get code here.
Change the implementation section using the code below:
Code 14.8: Using initializers code
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9
10
/ * *********** I m p l e m e n t a t i o n S e c t i o n ***************** * /
Rectangle : : Rectangle ( ) : width ( 1 ) , l e n g t h ( 2 ) {
c o u t << " H e l l o t h e r e ! My i d i s " << t h i s << e n d l ;
}
R e c t a n g l e : : R e c t a n g l e ( i n t w, i n t l ) : w i d t h (w) , l e n g t h ( l ) {
c o u t << " H e l l o t h e r e ! My i d i s " << t h i s << e n d l ;
}
void Rectangle : : printArea ( ) {
c o u t << " Area o f " << t h i s << " = " << w i d t h * l e n g t h << e n d l ;
}
14.6 Class Composition
14.6
157
Class Composition
A class can have as a member an object from another class.
Code 14.9: Class composition example
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4 / * ************** B i r t h d a y C l a s s ******************* * /
5 class Birthday {
6 private :
7
i n t month , day , y e a r ;
8 public :
9
B i r t h d a y ( i n t m, i n t d , i n t y )
10
: month (m) , day ( d ) , y e a r ( y ) {}
11
12
void p r i n t D a t e ( ) {
13
c o u t <<month << " / " << day << " / " << y e a r << e n d l ;
14
}
15 } ;
16 / * ************** P e r s o n C l a s s ******************* * /
17 c l a s s P e r s o n {
18 p r i v a t e :
19
s t r i n g name ;
20
Birthday dateOfBirth ;
21 p u b l i c :
22
Person ( s t r i n g n , Birthday b )
23
: name ( n ) , d a t e O f B i r t h ( b ) { }
24
25
void p r i n t I n f o ( ) {
26
c o u t << name << " was b o r n on : " ;
27
dateOfBirth . printDate ( ) ;
28
}
29 } ;
30 / * ************** Main ******************* * /
31 i n t main ( ) {
32
B i r t h d a y bDate ( 1 2 , 1 1 , 1 8 8 2 ) ;
33
Person peopleObj ( " F i o r e l l o H. LaGuardia " , bDate ) ;
34
peopleObj . p r i n t I n f o ( ) ;
35 }
<— Get code here.
1. Create a Major class with two private attributes, major name, and number of credits
and a public member function displayMajorInfo().
2. Create a Student class with private attributes, student name, age major and a public
member function displayStudentInfo().
15. Classes, Pointers, and Arrays
15.1
Pointers Revisited
IMPORTANT: First please review the material from chapter 9 on page 121.
Quick facts:
• A pointer is a variable that holds the address of another variable.
• The operator & provides the address of a variable.
• We use * when declaring a pointer. After declaration the operator * is used to get the
value from the variable the pointer is pointing to.
Code 15.1: Simple pointer example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t a = 5;
7
i n t * aP = &a ;
8
c o u t << " a = " << a << e n d l ;
9
c o u t << " * aP = " << * aP << e n d l ;
10
11
return 0;
12 }
Chapter 15. Classes, Pointers, and Arrays
160
15.2
Pointers and Some Special Operators
Code 15.2: Pointer example using some special operators
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
i n t * one = new i n t ;
7
c o u t << " * one = " <<
8
9
* one = 5 ;
10
c o u t << " * one = " <<
11
12
* one = NULL ;
13
c o u t << " * one = " <<
14
15
* one += 1 ;
16
c o u t << " * one = " <<
17
18
i n t * two = n u l l p t r ;
19
20
two = one ;
21
c o u t << " * two = " <<
22
23
return 0;
24 }
* one << e n d l ;
* one << e n d l ;
* one << e n d l ;
* one << e n d l ;
* two << e n d l ;
Can we have 2 pointers point at the same address? Show an example.
15.3
Arrays and Pointers
In chapter 9 we discussed some examples of using pointers when working with arrays.
Quick Facts:
1. Array variables are just pointers.
2. When we declare an array, we declare a pointer to its first element.
3. When we pass an array to a function, we pass a pointer to the first element instead of the
array values.
15.3 Arrays and Pointers
Code 15.3: Example of a dynamic array
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
6
const i n t sizeOne = 5;
7
i n t arrayOne [ sizeOne ] ;
8
9
f o r ( i n t i = 0 ; i < s i z e O n e ; i ++)
10
arrayOne [ i ]= i +1;
11
12
c o u t << " C o n t e n t o f a r r a y O n e : " ;
13
f o r ( i n t i = 0 ; i < s i z e O n e ; i ++)
14
c o u t << a r r a y O n e [ i ] << " " ;
15
16
c o u t << e n d l ;
17
18
c o n s t i n t sizeTwo = 5 ;
19
i n t * a r r a y T w o = new i n t [ s i z e T w o ] ;
20
21
f o r ( i n t i = 0 ; i < s i z e T w o ; i ++)
22
arrayTwo [ i ]= i +1;
23
24
c o u t << " C o n t e n t o f a r r a y T w o : " ;
25
f o r ( i n t i = 0 ; i < s i z e T w o ; i ++)
26
c o u t << a r r a y T w o [ i ] << " " ;
27
28
return 0;
29 }
<— Get code here.
What are the differences between arrayOne and arrayTwo?
Can we remove the const keyword from sizeOne? Why?
161
162
15.4
Chapter 15. Classes, Pointers, and Arrays
The this Keyword
The special keyword this is used to allow an object to refer to itself, meaning to have access (point)
at its own address.
Code 15.4: this pointer example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 / * ****** C l a s s D e c l a r a t i o n & D e f i n i t i o n ********** * /
5 c l a s s MyClass {
6 public :
7
MyClass ( i n t a ) : m y I n t ( a ) {}
8
void p rintV alues ( ) {
9
c o u t << m y I n t << e n d l ;
10
c o u t << t h i s −> m y I n t << e n d l ;
11
c o u t << ( * t h i s ) . m y I n t << e n d l ;
12
}
13 p r i v a t e :
14
i n t myInt ;
15 } ;
16
17 / * **************** Main S e c t i o n ****************** * /
18 i n t main ( ) {
19
MyClass o b j ( 1 0 0 ) ;
20
obj . printValues ( ) ;
21 }
15.5 Operator Overloading
163
Code 15.5: Another example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 / * *********** D e c l a r a t i o n S e c t i o n ***************** * /
5 c l a s s BankAccount {
6 private :
7
double balance ;
8 public :
9
BankAccount ( ) ;
10
BankAccount ( d o u b l e b a l a n c e ) ;
11
BankAccount& d e p o s i t ( d o u b l e money ) ;
12
v o i d w i t h d r a w ( d o u b l e money ) ;
13
double getBalance ( ) ;
14 } ;
15
16 / * *********** I m p l e m e n t a t i o n S e c t i o n ***************** * /
17 BankAccount : : BankAccount ( ) { b a l a n c e = 0 . 0 0 ; }
18 BankAccount : : BankAccount ( d o u b l e money ) { b a l a n c e = money ; }
19 BankAccount& BankAccount : : d e p o s i t ( d o u b l e money ) {
20
b a l a n c e += money ;
21
return * this ;
22 }
23 v o i d BankAccount : : w i t h d r a w ( d o u b l e money ) { b a l a n c e −= money ; }
24 d o u b l e BankAccount : : g e t B a l a n c e ( ) { r e t u r n b a l a n c e ; }
25
26 / * **************** Main S e c t i o n ******************** * /
27 i n t main ( ) {
28
BankAccount myAccount ;
29
c o u t << " I n i t i a l b a l a n c e = " << myAccount . g e t B a l a n c e ( ) << e n d l ;
30
31
myAccount . d e p o s i t ( 5 0 ) ;
32
c o u t << " B a l a n c e 1 = " << myAccount . g e t B a l a n c e ( ) << e n d l ;
33
34
myAccount . d e p o s i t ( 3 0 ) . d e p o s i t ( 5 0 ) . d e p o s i t ( 2 0 ) ;
35
c o u t << " B a l a n c e 2 = " << myAccount . g e t B a l a n c e ( ) << e n d l ;
36
37
return 0;
38 }
15.5
Operator Overloading
Most C++ operators can be overloaded. Overloading an operator means to define a new function/use
for the operator as compared to the original built-in function.
Chapter 15. Classes, Pointers, and Arrays
164
Code 15.6: Operator overloading example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
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23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
# include <iostream >
u s i n g namespace s t d ;
/ * *********** D e c l a r a t i o n S e c t i o n ***************** * /
class Rectangle {
private :
i n t width , l e n g t h ;
public :
Rectangle ( ) ;
R e c t a n g l e ( i n t w, i n t l ) ;
void printArea ( ) ;
void d i s p l a y I n f o ( ) ;
R e c t a n g l e o p e r a t o r + ( R e c t a n g l e& r ) ;
};
/ * *********** I m p l e m e n t a t i o n S e c t i o n ***************** * /
Rectangle : : Rectangle ( ) { width = 1 , l e n g t h = 2; }
R e c t a n g l e : : R e c t a n g l e ( i n t w, i n t l ) { w i d t h = w, l e n g t h = l ; }
void Rectangle : : printArea ( ) {
c o u t << " Area o f " << t h i s << " = " << w i d t h * l e n g t h << e n d l ;
}
void Rectangle : : d i s p l a y I n f o ( ) {
c o u t << " I am a " << w i d t h << " x " << l e n g t h << " r e c t a n g l e "
<< " w i t h i d " << t h i s << e n d l ;
}
R e c t a n g l e R e c t a n g l e : : o p e r a t o r + ( R e c t a n g l e& r ) {
R e c t a n g l e temp ;
temp . w i d t h = t h i s −> w i d t h + r . w i d t h ;
temp . l e n g t h = t h i s −> l e n g t h + r . l e n g t h ;
r e t u r n temp ;
}
/ * **************** Main S e c t i o n ******************** * /
i n t main ( ) {
R e c t a n g l e r1 , r 2 ( 5 , 7 ) , r 3 ;
r1 . d i s p l a y I n f o ( ) ;
r2 . d i s p l a y I n f o ( ) ;
r3 . d i s p l a y I n f o ( ) ;
r3=r1+r2 ;
r3 . d i s p l a y I n f o ( ) ;
r1 . printArea ( ) ;
r2 . printArea ( ) ;
r3 . printArea ( ) ;
return 0;
}
Change the + operator overload to work with a rectangle object and an integer (e.g r1+2)
ch will add the integer to both the width and the length of the rectangle.
16. Recursion
16.1
Recursive Functions
Recursion is a technique when a function calls itself. To avoid infinite loops each recursive function
has a mechanism of ending the recursion. Each recursive function has a base case.
Example: Recall the program 5.4 that defines and tests a factorial function using a for loop. Here
we change the factorial function to a recursive function.
166
Chapter 16. Recursion
Code 16.1: Using recursion to calculate the factorial of a number
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int factorial ( int );
5
6 i n t main ( ) {
7
8
i n t number = 5 ;
9
10
c o u t << number << " ! = " << f a c t o r i a l ( number ) << e n d l ;
11
12
return 0;
13 } / / end main ( )
14
15 i n t f a c t o r i a l ( i n t x ) {
16
17
i f ( x==0 | | x ==1)
18
return 1;
19
else
20
return x * f a c t o r i a l (x −1);
21
22 } / / end f a c t o r i a l ( )
During recursion, a special area of memory called the stack is utilized to store the information as
the multiple function calls are executed. Values that are stored in the stack follow the last in – first
out (LIFO) order. The following picture illustrates the factorial recursive process.
Which of the two approaches (iterative or recursive) is better in this case?
16.1 Recursive Functions
167
Write a program that uses a function sum(int) that takes as an argument a positive integer
n and returns the sum of the first n positive integers. Use a while loop. Then write a
recursive function that performs the same task.
Desired output:
Enter a positive integer: 5
The sum of the first 5 positive integers is: 15
Try using n=50,000 for each of the programs. What do you notice? Which version is a
better choice for this example? Can we further optimize the code?
Additional example: The Fibonacci series.
What is the Fibonacci series?
168
Chapter 16. Recursion
Code 16.2: Fibonacci example using iteration
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int fibonacci ( int x );
5
6 i n t main ( ) {
7
i n t number = 6 ; / / <−− E n t e r t e r m h e r e
8
c o u t << " The " << number << " − t h F i b o n a c c i i s : " ;
9
c o u t << f i b o n a c c i ( number ) << e n d l ;
10
return 0;
11 } / / end main ( )
12
13 i n t f i b o n a c c i ( i n t x ) {
14
i n t i = 0 , j = 1 , k = 1 , sum = 0 ;
15
while ( i < x −1){
16
sum= j +k ;
17
j =k ;
18
k=sum ;
19
i ++;
20
}
21
return j ;
22 } / / end f i b o n a c c i ( )
Code 16.3: Fibonacci example using recursion
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int fibonacci ( int x );
5
6 i n t main ( ) {
7
i n t number = 6 ; / / <−− E n t e r t e r m h e r e
8
c o u t << " The " << number << " − t h F i b o n a c c i i s : " ;
9
c o u t << f i b o n a c c i ( number ) << e n d l ;
10
return 0;
11 } / / end main ( )
12
13 i n t f i b o n a c c i ( i n t x ) {
14
i f ( x==1 | | x ==2)
15
return 1;
16
else
17
r e t u r n f i b o n a c c i ( x −1) + f i b o n a c c i ( x − 2 ) ;
18 } / / end f i b o n a c c i ( )
16.2 More on Recursion
169
Write a program that uses a function power(base,exponent) which when invoked returns
baseexponent .
Desired output:
Enter base: 5
Enter exponent: 3
5 to the power 3 is: 125
Example: Print the prime factorization of a given number.
Code 16.4: Prime factorization of a number
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void g e t _ d i v i s o r s ( i n t n ) ;
5
6 i n t main ( ) {
7
i n t n = 0;
8
c o u t << " E n t e r an i n t e g e r : " ;
9
c i n >> n ;
10
get_divisors (n );
11
return 0;
12 } / / end main
13
14 v o i d g e t _ d i v i s o r s ( i n t n ) {
15
f o r ( i n t i = 2 ; i < n ; i ++)
16
i f ( n \% i == 0 ) {
17
c o u t << i << " , " ;
18
get_divisors (n/ i );
19
return ;
20
}
21
c o u t << n ;
22 } / / end g e t _ d i v i s o r s ( )
<— Get code here.
16.2
More on Recursion
IMPORTANT: First please review the material from chapter ?? on page ??.
Quick Facts:
1. Recursion is a technique that solves a problem by first finding the solution for a smaller,
simpler problem and use the information to build up to the final answer.
2. In C++, like many other languages, we implement a recursive solution by allowing a
function to call itself.
Chapter 16. Recursion
170
3. Each recursive function has two components, the base case and the recursive step.
4. Both void functions and those returning a value can be recursive.
Code 16.5: Example void recursive function - Convert to Binary
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void toBinary ( i n t ) ;
5
6 i n t main ( ) {
7
i n t number = 5 ;
8
c o u t << " D e c i m a l : " << number << e n d l ;
9
c o u t << " B i n a r y : " ;
10
t o B i n a r y ( number ) ;
11
return 0;
12 }
13
14 v o i d t o B i n a r y ( i n t n ) {
15
i f ( n == 0 )
16
return ;
17
18
toBinary (n / 2 ) ;
19
c o u t << n%2;
20
return ;
21 }
Write an iterative version of the ’covert to binary’ program.
Can we generalize this algorithm to convert to other bases?
16.2 More on Recursion
Code 16.6: Iterative program to reverse the digits of an integer
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 void printReverse ( i n t ) ;
5
6 i n t main ( ) {
7
i n t number = 1 2 3 4 5 ;
8
c o u t << " O r i g i n a l : " << number << e n d l ;
9
c o u t << " R e v e r s e d : " ;
10
p r i n t R e v e r s e ( number ) ;
11
return 0;
12 }
13
14 v o i d p r i n t R e v e r s e ( i n t x ) {
15
while ( x !=0){
16
c o u t << x %10;
17
x=x / 1 0 ;
18
}
19 }
Write a recursive version of the ’reverse digits’ program.
171
Chapter 16. Recursion
172
Code 16.7: Determine if string is a palindrome - recursive
1
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4
5
6
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13
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16
17
18
19
20
21
22
23
24
25
26
27
28
# include <iostream >
# include <string >
u s i n g namespace s t d ;
bool isPalindrome ( s t r i n g ) ;
i n t main ( ) {
s t r i n g mystr ;
c o u t << " E n t e r a s t r i n g : " ;
g e t l i n e ( cin , mystr ) ;
i f ( isPalindrome ( mystr ) )
c o u t << m y s t r << " i s a p a l i n d r o m e \ n " ;
else
c o u t << m y s t r << " i s n o t a p a l i n d r o m e \ n " ;
}
bool isPalindrome ( s t r i n g s t r ){
int length = str . length ( ) ;
i f ( l e n g t h <= 1 )
return true ;
i f ( s t r [ 0 ] == s t r [ l e n g t h − 1 ] )
return isPalindrome ( s t r . substr (1 , ( length − 2 ) ) ) ;
return false ;
}
<— Get code here (recursive version).
<— Get code here (iterative version).
16.3
Practice Questions
1. What is the meaning of the following in the context of Computer Science?
(a) recursion base case:
(b) recursive step:
16.3 Practice Questions
173
(c) iteration vs recursion:
2. True-False questions – Circle your choice
(a) The main reason we use recursion is because it typically uses less memory than iteration.
( True - False )
3. The following program should print the sum of the first n positive integers. Find and fix the
errors in the code.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t number ;
6
c o u t << " E n t e r a P o s i t i v e I n t e g e r : " ;
7
c i n >> number ;
8
c o u t << " The sum o f t h e f i r s t " << number ;
9
c o u t << " i n t e g e r s i s : " << sum ( number ) << e n d l ;
10
return 0;
11 } / / end main ( ) f u n c t i o n
12
13 i n t sum ( i n t x ) {
14
i f ( x == 1 )
15
return 1;
16
else
17
r e t u r n x + sum ( x ) ;
18 }
Sample output:
Enter a Positive Integer: 5
The sum of the first 5 integers is: 15
174
4. Write the exact output.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 int f ( int x );
5
6 i n t main ( ) {
7
i n t number = 5 ;
8
c o u t << f ( number ) ;
9
return 0;
10 } / / end main ( ) f u n c t i o n
11
12 i n t f ( i n t x ) {
13
i f ( x < 2)
14
return 1;
15
else
16
r e t u r n f ( x −1) * f ( x −2) + 1 ;
17 }
Chapter 16. Recursion
16.3 Practice Questions
175
5. The following program should print the prime factorization of a number entered by the user.
Fix all the errors and make the necessary changes so that the code produces the desired
output. Sample output is provided.
1
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3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
# include <iostream >
# i n c l u d e <cmath >
u s i n g namespace s t d ;
void g e t _ d i v i s o r s ( i n t n ) ;
i n t main ( ) {
i n t n = 0;
c o u t << " E n t e r an i n t e g e r : " ;
c i n >> n ;
c o u t << e n d l ;
return 0;
}
void g e t _ d i v i s o r s ( i n t n ) {
int i ;
f o r ( i = 2 ; i <= s q r t _ o f _ n ; i ++)
i f ( n % i == 5 ) {
c o u t << i << " , " ;
get_divisors (n \ i );
return ;
}
c o u t << n ;
}
Sample output:
Enter an integer: 24
2,2,2,3
6. Write a program that uses a recursive function power(base,exponent) which when invoked
returns basee xponent.
Sample output:
Enter the Base: 5
Enter the Exponent: 3
5 to the power 3 = 125
Chapter 16. Recursion
176
7. Write a program that uses a function sum(int) that takes as an argument a positive integer n
and returns the sum of the first n positive integers. Use a while loop. Then write a recursive
function that performs the same task. .
Sample output:
Enter a positive integer: 5
The sum of the first 5 positive integers is: 15
8. Write a program that uses a function gcf(int,int) that takes as arguments two positive integers
and returns their GCF (Greatest Common Factor) sum of the first n positive integers. First
use a loop. Then write a recursive function that performs the same task.
Sample output:
Enter first integer: 50
Enter second integer: 30
Their gcf is: 10
17. Inheritance
17.1
Inheritance
Inheritance is a key feature of object oriented programming. It allows new classes to adopt attributes
and functionality from existing classes. The original class is called the base class and the new class
is the derived class.
Chapter 17. Inheritance
178
Code 17.1: Simple inheritance example
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 c l a s s Person {
6 public :
7
s t r i n g name ;
8
i n t age ;
9 };
10
11 c l a s s S t u d e n t : p u b l i c P e r s o n {
12 p u b l i c :
13
d o u b l e gpa ;
14 } ;
15
16 i n t main ( ) {
17
Student st1 ;
18
s t 1 . name = " Bob " ;
19
s t 1 . age = 20;
20
s t 1 . gpa = 3 . 5 5 ;
21
22
c o u t << s t 1 . name ;
23
c o u t << " i s a " << s t 1 . a g e << " y e a r o l d s t u d e n t " ;
24
c o u t << " w i t h a gpa o f " << s t 1 . gpa << e n d l ;
25
return 0;
26 }
Which one is the base class and which one the derived class?
Alternatively the terms parent class and child class are also used. Which one they are in
our example?
Substitute the keyword public with protected inside the Person class. Does it work?
Repeat using the keyword private.
17.1 Inheritance
179
Code 17.2: Simple inheritance example with added components
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 c l a s s Person {
6 public :
7
s t r i n g name ;
8
i n t age ;
9 };
10
11 c l a s s S t u d e n t : p u b l i c P e r s o n {
12 p r i v a t e :
13
d o u b l e gpa ;
14 p u b l i c :
15
Student ( s t r i n g n , i n t a , double g ){
16
name = n ;
17
age = a ;
18
gpa = g ;
19
}
20
21
void p r i n t I n f o ( ) {
22
c o u t << name ;
23
c o u t << " i s a " << a g e << " y e a r o l d s t u d e n t " ;
24
c o u t << " w i t h a gpa o f " << gpa << e n d l ;
25
}
26 } ;
27
28 i n t main ( ) {
29
S t u d e n t s t 1 ( " Bob " , 2 0 , 3 . 5 5 ) ;
30
st1 . printInfo ( ) ;
31
return 0;
32 }
Substitute the keyword public with protected inside the Person class. Does it work this
time? Repeat using the keyword private. If any of the attempts does not work what can
we do to fix it?
Chapter 17. Inheritance
180
17.2
Inheritance and Constructors
Constructors and destructors are not inherited from the base class to the derived class.
Code 17.3: Constructors in inheritance example
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 c l a s s Person {
6 protected :
7
s t r i n g name ;
8
i n t age ;
9 public :
10
P e r s o n ( ) { c o u t << "New p e r s o n c r e a t e d . " << e n d l ; }
11
~ P e r s o n ( ) { c o u t << " P e r s o n d e l e t e d . " << e n d l ; }
12
13 } ;
14
15 c l a s s S t u d e n t : p u b l i c P e r s o n {
16 p r i v a t e :
17
d o u b l e gpa ;
18 p u b l i c :
19
Student ( s t r i n g n , i n t a , double g ){
20
c o u t << "New s t u d e n t c r e a t e d . " << e n d l ;
21
name = n ;
22
age = a ;
23
gpa = g ;
24
}
25
26
~ S t u d e n t ( ) { c o u t << " S t u d e n t d e l e t e d . " << e n d l ; }
27
28
void p r i n t I n f o ( ) {
29
c o u t << name ;
30
c o u t << " i s a " << a g e << " y e a r o l d s t u d e n t " ;
31
c o u t << " w i t h a gpa o f " << gpa << e n d l ;
32
}
33 } ;
34
35 i n t main ( ) {
36
S t u d e n t s t 1 ( " Bob " , 2 0 , 3 . 5 5 ) ;
37
st1 . printInfo ( ) ;
38
return 0;
39 }
Run the program. What do you notice about the order in which constructors and destructors are executed? What can we conclude regarding the relation betwen the base and
derived constructors and destructors?
17.2 Inheritance and Constructors
Code 17.4: Constructors in inheritance example - Explicit constructor call
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 c l a s s Person {
6 protected :
7
s t r i n g name ;
8
i n t age ;
9 public :
10
P e r s o n ( ) : name ( " " ) , a g e ( 0 )
11
{ c o u t << "New p e r s o n c r e a t e d . " << e n d l ; }
12
P e r s o n ( s t r i n g n , i n t a ) : name ( n ) , a g e ( a )
13
{ c o u t << "New p e r s o n c r e a t e d . " << e n d l ; }
14
~ P e r s o n ( ) { c o u t << " P e r s o n d e l e t e d . " << e n d l ; }
15 } ;
16
17 c l a s s S t u d e n t : p u b l i c P e r s o n {
18 p r i v a t e :
19
d o u b l e gpa ;
20 p u b l i c :
21
S t u d e n t ( ) : P e r s o n ( ) , gpa ( 0 . 0 )
22
{ c o u t << "New s t u d e n t c r e a t e d . " << e n d l ; }
23
S t u d e n t ( s t r i n g n , i n t a , d o u b l e g ) : P e r s o n ( n , a ) , gpa ( g )
24
{ c o u t << "New s t u d e n t c r e a t e d . " << e n d l ; }
25
~ S t u d e n t ( ) { c o u t << " S t u d e n t d e l e t e d . " << e n d l ; }
26
27
void p r i n t I n f o ( ) {
28
c o u t << name ;
29
c o u t << " i s a " << a g e << " y e a r o l d s t u d e n t " ;
30
c o u t << " w i t h a gpa o f " << gpa << e n d l ;
31
}
32 } ;
33 i n t main ( ) {
34
S t u d e n t s t 1 ( " Bob " , 2 0 , 3 . 5 5 ) ;
35
st1 . printInfo ( ) ;
36
return 0;
37 }
What are the advantages of calling a constructor explicitly?
Is it best to keep attributes protected or private?
181
Chapter 17. Inheritance
182
17.3
Inheriting Functionality
Member functions are inherited similar to member attributes.
Code 17.5: Inheriting member functions
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 c l a s s Person {
6 protected :
7
s t r i n g name ;
8
i n t age ;
9 public :
10
P e r s o n ( ) : name ( " " ) , a g e ( 0 )
11
{ c o u t << "New p e r s o n c r e a t e d . " << e n d l ; }
12
Person ( s t r i n g n , i n t a )
13
: name ( n ) , a g e ( a )
14
{ c o u t << "New p e r s o n c r e a t e d . " << e n d l ; }
15
void sayHello ( ) {
16
c o u t << " H e l l o I am " << name << " . " ;
17
c o u t << " I am a p e r s o n . " << e n d l ;
18
}
19
~ P e r s o n ( ) { c o u t << " P e r s o n d e l e t e d . " << e n d l ; }
20 } ;
21
22 c l a s s S t u d e n t : p u b l i c P e r s o n {
23 p r i v a t e :
24
d o u b l e gpa ;
25 p u b l i c :
26
S t u d e n t ( ) : P e r s o n ( ) , gpa ( 0 . 0 )
27
{ c o u t << "New s t u d e n t c r e a t e d . " << e n d l ; }
28
Student ( s t r i n g n , i n t a , double g )
29
: P e r s o n ( n , a ) , gpa ( g )
30
{ c o u t << "New s t u d e n t c r e a t e d . " << e n d l ; }
31
~ S t u d e n t ( ) { c o u t << " S t u d e n t d e l e t e d . " << e n d l ; }
32 } ;
33
34 i n t main ( ) {
35
S t u d e n t s t 1 ( " Bob " , 2 0 , 3 . 5 5 ) ;
36
st1 . sayHello ( ) ;
37
return 0;
38 }
17.3 Inheriting Functionality
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4
183
void sayHello ( ) {
c o u t << " H e l l o I am " << name << " . " ;
c o u t << " I am a s t u d e n t . " << e n d l ;
}
Add the above function definition to the Student class definition and run the program.
What change do you observe?
1
2
3
4
v o i d s a y H e l l o ( s t r i n g mood ) {
c o u t << " H e l l o I am " << name << " . " ;
c o u t << " I am a " << mood << " s t u d e n t . " << e n d l ;
}
Change the function definition to the one above and run again the program. Any observations?
Chapter 17. Inheritance
184
17.4
Multiple Inheritance
Multiple inheritance is allowed in C++. A child (derived) class can have more than one parent
(base) class.
Code 17.6: Multiple inheritance example
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5 class Student {
6 public :
7
s t r i n g name ;
8
s t r i n g major ;
9
S t u d e n t ( ) { c o u t << " S t u d e n t c r e a t e d . " << e n d l ; }
10
~ S t u d e n t ( ) { c o u t << " S t u d e n t d e l e t e d . " << e n d l ; }
11
v o i d s a y H e l l o ( ) { c o u t << " H e l l o I am a s t u d e n t . " << e n d l ; }
12 } ;
13
14 c l a s s T e a c h e r {
15 p u b l i c :
16
s t r i n g name1 ;
17
s t r i n g rank ;
18
T e a c h e r ( ) { c o u t << " T e a c h e r c r e a t e d . " << e n d l ; }
19
~ T e a c h e r ( ) { c o u t << " T e a c h e r d e l e t e d . " << e n d l ; }
20
v o i d s a y H e l l o ( ) { c o u t << " H e l l o I am a t e a c h e r . " << e n d l ; }
21 } ;
22
23 c l a s s G r a d u a t e I n s t r u c t o r : p u b l i c S t u d e n t , p u b l i c T e a c h e r {
24 p u b l i c :
25
G r a d u a t e I n s t r u c t o r ( ) { c o u t << " I n s t r u c t o r c r e a t e d . " << e n d l ; }
26
~ G r a d u a t e I n s t r u c t o r ( ) { c o u t << " I n s t r u c t o r d e l e t e d . " << e n d l ; }
27 } ;
28
29 i n t main ( ) {
30
G r a d u a t e I n s t r u c t o r gi1 ;
31
g i 1 . name= " Bob " ;
32
gi1 . rank=" I n s t r u c t o r " ;
33
c o u t << g i 1 . name << " i s an " << g i 1 . r a n k << e n d l ;
34
return 0;
35 }
What are the benefits and risks of using multiple inheritance?
17.5 Multilevel Inheritance
17.5
185
Multilevel Inheritance
Code 17.7: Multilevel inheritance example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 c l a s s Major {
5 public :
6
i n t id ;
7
Major ( ) { c o u t << "New m a j o r . " << e n d l ; }
8
~ Major ( ) { c o u t << " Major d e l e t e d . " << e n d l ; }
9 };
10
11 c l a s s E n g i n e e r i n g : p u b l i c Major {
12 p u b l i c :
13
E n g i n e e r i n g ( ) { c o u t << "New e n g i n e e r i n g m a j o r . " << e n d l ; }
14
~ E n g i n e e r i n g ( ) { c o u t << " E n g i n e e r i n g m a j o r d e l e t e d . " << e n d l ; }
15 } ;
16
17 c l a s s C i v i l E n g i n e e r i n g : p u b l i c E n g i n e e r i n g {
18 p u b l i c :
19
C i v i l E n g i n e e r i n g ( ) { c o u t << "New c i v i l eng . m a j o r . " << e n d l ; }
20
~ C i v i l E n g i n e e r i n g ( ) { c o u t << " C i v i l eng . d e l e t e d . " << e n d l ; }
21 } ;
22
23 i n t main ( ) {
24
C i v i l E n g i n e e r i n g major1 ;
25
major1 . id =10;
26
c o u t << " Major w i t h i d : " << m a j o r 1 . i d << e n d l ;
27
return 0;
28 }
18. Polymorphism
18.1
Polymorphism and Virtual Functions
Polymorphism is an important mechanism in object oriented programming. The term itself means
many forms. When two or more classes are related to each other via inheritance, we want to be
able to determine which inherited member functions are executed during the life of a program.
Polymorphism allows for this decision to be made during the execution of the program by adapting
to the type of object is currently working with at the time the decision needs to be made. This is
also called late binding. Virtual functions are used for this purpose. Before we look at the first
example of virtual functions lets revisit functionality inheritance, function overloading and function
redefinitions.
188
Chapter 18. Polymorphism
Code 18.1: Overloading and redefining functions example
1 # include <iostream >
2 # include <string >
3 u s i n g namespace s t d ;
4
5
6 c l a s s Person {
7 public :
8
P e r s o n ( ) { c o u t << "New p e r s o n c r e a t e d . " << e n d l ; }
9
~ P e r s o n ( ) { c o u t << " P e r s o n d e l e t e d . " << e n d l ; }
10
v o i d s a y H e l l o ( ) { c o u t << " H e l l o I am a p e r s o n . " << e n d l ; }
11
v o i d s a y H e l l o ( s t r i n g name ) {
12
c o u t << " I am " << name << " . I am a p e r s o n . " << e n d l ; }
13 } ;
14
15 c l a s s S t u d e n t : p u b l i c P e r s o n {
16 p u b l i c :
17
S t u d e n t ( ) { c o u t << "New s t u d e n t c r e a t e d . " << e n d l ; }
18
~ S t u d e n t ( ) { c o u t << " S t u d e n t d e l e t e d . " << e n d l ; }
19
v o i d s a y H e l l o ( ) { c o u t << " H e l l o I am a s t u d e n t . " << e n d l ; }
20
v o i d s a y H e l l o ( s t r i n g name ) {
21
c o u t << " I am " << name << " . I am a s t u d e n t . " << e n d l ; }
22 } ;
23
24 i n t main ( ) {
25
Person pr1 ;
26
Student st1 ;
27
pr1 . sayHello ( ) ;
28
p r 1 . s a y H e l l o ( " Bob " ) ;
29
st1 . sayHello ( ) ;
30
s t 1 . s a y H e l l o ( " John " ) ;
31
return 0;
32 }
In the example above we have both function overloading and function redefining. The decision on
which function will be called during execution is made at compilation time. This is also referred
to as static binding. In the next example we will use virtual functions and discuss the difference
between static and late binding.
18.1 Polymorphism and Virtual Functions
Code 18.2: Virtual function example
1
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# include <iostream >
u s i n g namespace s t d ;
c l a s s Shape {
public :
int height ;
Shape ( ) { h e i g h t = 1 ; }
Shape ( i n t h ) { h e i g h t =h ; }
v i r t u a l v o i d drawShape ( ) {
c o u t << " Shape : h e i g h t : " << h e i g h t << e n d l ;
}
};
c l a s s S q u a r e : p u b l i c Shape {
public :
Square ( ) { h e i g h t =1;}
S q u a r e ( i n t h ) { h e i g h t =h ; }
v o i d drawShape ( ) {
c o u t << " S q u a r e : h e i g h t : " << h e i g h t << e n d l ;
f o r ( i n t i = 0 ; i < h e i g h t ; i ++){
f o r ( i n t j = 0 ; j < h e i g h t * 2 ; j ++) { c o u t << ’ * ’ ; }
c o u t << e n d l ;
}
c o u t << e n d l << e n d l ;
}
};
c l a s s T r i a n g l e : p u b l i c Shape {
public :
T r i a n g l e ( ) { h e i g h t =1;}
T r i a n g l e ( i n t h ) { h e i g h t =h ; }
v o i d drawShape ( ) {
c o u t << " T r i a n g l e : h e i g h t : " << h e i g h t << e n d l ;
f o r ( i n t i = 1 ; i <=5; i ++) {
f o r ( i n t j = 1 ; j <=5− i ; j ++) { c o u t << ’ ’ ; }
f o r ( i n t k = 1 ; k <=2 * i − 1 ; k++ ) { c o u t << ’ * ’ ; }
c o u t << ’ \ n ’ ;
}
c o u t << e n d l ;
}
};
i n t main ( ) {
S q u a r e mySquare ( 4 ) ;
Triangle myTriangle ( 5 ) ;
Shape myShape ( 6 ) ;
Shape * s h a p e p 1 = &mySquare ;
Shape * s h a p e p 2 = &m y T r i a n g l e ;
Shape * s h a p e p 3 = &myShape ;
s h a p e p 1 −> drawShape ( ) ;
s h a p e p 2 −> drawShape ( ) ;
s h a p e p 3 −> drawShape ( ) ;
return 0;
}
<— Get code here.
189
190
Chapter 18. Polymorphism
Remove the keyword virtual and run the program. What do you observe?
Use the dot (.) operator instead of pointers to call method drawShape().
Add the new function newDraw() and change main() as shown below. What do you
notice? What does that tell you about the usefulness of virtual functions?
Code 18.3: Try now additions/changes
1 v o i d newDraw ( Shape * s ) {
2
c o u t << " H e l l o I am t h e new f u n c t i o n ! ! ! " << e n d l ;
3
s −> drawShape ( ) ;
4 }
5
6 i n t main ( ) {
7
S q u a r e mySquare ( 4 ) ;
8
Triangle myTriangle ( 5 ) ;
9
Shape myShape ( 6 ) ;
10
newDraw(& mySquare ) ;
11
newDraw(& m y T r i a n g l e ) ;
12
newDraw(&myShape ) ;
13
return 0;
14 }
What is the difference between redefining and overriding?
18.2 Abstract Classes
18.2
191
Abstract Classes
A class with one or more pure virtual function is an abstract class.
A pure virtual function is only declared but not defined within the same class. To declare a pure
virtual function we use the following syntax.
The pure virtual function format
virtual return_type function_name (parameter list) = 0;
Code 18.4: Virtual function example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 c l a s s Animal {
5 public :
6
Animal ( s t r i n g n ) : name ( n ) {}
7
v i r t u a l ~ Animal ( ) {}
8
v i r t u a l v o i d makeNoise ( ) = 0 ;
9 protected :
10
s t r i n g name ;
11 } ;
12
13
14 c l a s s Dog : p u b l i c Animal {
15 p u b l i c :
16
Dog ( s t r i n g n ) : Animal ( n ) {}
17
v o i d makeNoise ( ) o v e r r i d e {
18
c o u t << name << " s a y s woof ! " << e n d l ;
19
}
20 } ;
21
22 c l a s s C a t : p u b l i c Animal {
23 p u b l i c :
24
C a t ( s t r i n g n ) : Animal ( n ) {}
25
v o i d makeNoise ( ) o v e r r i d e {
26
c o u t << name << " s a y s meow ! " << e n d l ;
27
}
28 } ;
29
30 i n t main ( ) {
31
Dog myDog ( " L a s s i e " ) ;
32
myDog . makeNoise ( ) ;
33
C a t myCat ( " B e l l a " ) ;
34
myCat . makeNoise ( ) ;
35
return 0;
36 }
Chapter 18. Polymorphism
192
Which of the three classes is abstract?
Is override mandatory when defining inherited virtual functions?
Can we create an object of type Animal using the above class definitions?
Remove the makeNoise() function definition from the Dog class. Does the program
work?
In main() add an array of four animals, two dogs and two cats. Then use a for loop to call
the makeNoise() function for each array element.
19. Templates
19.1
Background
Before we introduce templates, we look back at a simple function which swaps the values of two
variables.
Code 19.1: Function swapValues() example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 v o i d s w a p V a l u e s ( i n t& one , i n t& two ) {
5
i n t temp = one ;
6
one = two ;
7
two = temp ;
8 } / / end swap
9
10 i n t main ( ) {
11
i n t f i r s t =3 , s e c o n d = 5 ;
12
c o u t << " B e f o r e swap . " << e n d l ;
13
c o u t << " f i r s t = " << f i r s t << e n d l ;
14
c o u t << " s e c o n d = " << s e c o n d << e n d l << e n d l ;
15
16
swapValues ( f i r s t , second ) ;
17
18
c o u t << " A f t e r swap . " << e n d l ;
19
c o u t << " f i r s t = " << f i r s t << e n d l ;
20
c o u t << " s e c o n d = " << s e c o n d << e n d l << e n d l ;
21
22
return 0;
23 } / / end main
Chapter 19. Templates
194
Change the swapValues() definition to work with two double values. How about two
char values?
Add the following class definition to the program and make any necessary changes for
the function to swap two Person objects.
Code 19.2: Class Person definition
1
2
3
4
5
6
7
c l a s s Person {
private :
s t r i n g name ;
public :
P e r s o n ( s t r i n g n ) : name ( n ) {}
s t r i n g getName ( ) { r e t u r n name ; }
};
What could we do if we want all of the above examples to work in the same program?
19.2 Function Templates
19.2
195
Function Templates
Function templates are used when we wish to declare and define a function which works for multiple
value types. The following example illustrates a simple template for the swapValues() function.
Code 19.3: First function template example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 t e m p l a t e < t y p e n a m e T>
5 v o i d s w a p V a l u e s ( T& one , T& two ) {
6
T temp = one ;
7
one = two ;
8
two = temp ;
9 } / / end s w a p V a l u e s
10
11 i n t main ( ) {
12
13
i n t f i r s t =3 , s e c o n d = 5 ;
14
c o u t << " B e f o r e swap . " << e n d l ;
15
c o u t << " f i r s t = " << f i r s t << e n d l ;
16
c o u t << " s e c o n d = " << s e c o n d << e n d l << e n d l ;
17
18
swapValues ( f i r s t , second ) ;
19
20
c o u t << " A f t e r swap . " << e n d l ;
21
c o u t << " f i r s t = " << f i r s t << e n d l ;
22
c o u t << " s e c o n d = " << s e c o n d << e n d l << e n d l ;
23
24
return 0;
25 } / / end main
Change the keyword typename with the keyword class and run the program. Does it
work?
Do we need to use T for the typename?
Change main() to test other types of values and run the program. Do not change the
definition of swapValues(). Does it work?
Can we separate the template function declaration from it definition?
Chapter 19. Templates
196
Write a function template named largest(). The function takes three values of the same
type as arguments and returns the largest of the three. The function should also work
if the values are the same. Write a program to test the function for different values. A
sample output is given below as a reference.
Desired output format:
Values are: 4 4 3
The largest value is: 4
Consider the Rectangle class definition below. Make all the necessary changes to make
the largest() function template work with Rectangle types in a meaningful way.
Code 19.4: Rectangle class definition
1 / * *********** D e c l a r a t i o n S e c t i o n ***************** * /
2 class Rectangle {
3 private :
4
i n t width , l e n g t h ;
5 public :
6
Rectangle ( ) ;
7
R e c t a n g l e ( i n t w, i n t l ) ;
8
R e c t a n g l e o p e r a t o r + ( R e c t a n g l e& r ) ;
9 };
10 / * *********** I m p l e m e n t a t i o n S e c t i o n ***************** * /
11 R e c t a n g l e : : R e c t a n g l e ( ) { w i d t h = 1 , l e n g t h = 2 ; }
12 R e c t a n g l e : : R e c t a n g l e ( i n t w, i n t l ) { w i d t h = w, l e n g t h = l ; }
13 R e c t a n g l e R e c t a n g l e : : o p e r a t o r + ( R e c t a n g l e& r ) {
14
R e c t a n g l e temp ;
15
temp . w i d t h = t h i s −> w i d t h + r . w i d t h ;
16
temp . l e n g t h = t h i s −> l e n g t h + r . l e n g t h ;
17
r e t u r n temp ;
18 }
19.3 Class Templates
19.3
197
Class Templates
Class templates are defined in a similar way as function templates. Below is a simple example
adopted from the the book.
Code 19.5: Class template example
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# include <iostream >
u s i n g namespace s t d ;
t e m p l a t e < c l a s s T>
class Pair {
public :
Pair ( );
P a i r (T f i r s t V a l u e , T secondValue ) ;
void p r i n t P a i r ( ) const ;
private :
T first ;
T second ;
};
t e m p l a t e < c l a s s T>
P a i r <T > : : P a i r ( T f i r s t V a l u e , T s e c o n d V a l u e ) {
first = firstValue ;
second = secondValue ;
}
t e m p l a t e < c l a s s T>
v o i d P a i r <T > : : p r i n t P a i r ( ) c o n s t {
c o u t << " ( " << f i r s t << " , " << s e c o n d << " ) " ;
}
i n t main ( ) {
P a i r < i n t > p1 ( 3 , 5 ) ;
P a i r < c h a r > p2 ( ’ a ’ , ’ b ’ ) ;
c o u t << " F i r s t p a i r : " ;
p1 . p r i n t P a i r ( ) ;
c o u t << e n d l ;
c o u t << " Second p a i r : " ;
p2 . p r i n t P a i r ( ) ;
return 0;
} / / end main
Give the definition for the default Pair constructor.
Define a non-member template function T addValues(Pair<T> & myPair) which returns
the sum of the two values in the pair. Add any necessary components to the class Pair.
Test the function from main for different value types.
20. Linked Data Structures
20.1
Linked Lists
Linked Lists allow us to create flexible and dynamic collections of data. Linked Lists do not have a
fixed size and can expand or reduce in size as needed. Elements belonging to a linked list connect
to one another via pointers. Before we introduce an example of a linked list we start with a small
program using structs and pointers.
Code 20.1: Starting example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 s t r u c t Node {
5
i n t value ;
6
Node * n e x t ;
7 };
8
9 i n t main ( ) {
10
Node * one = new Node ;
11
one −> n e x t = NULL ;
12
one −> v a l u e = 1 ;
13
c o u t << one −> v a l u e << e n d l ;
14 }
What is the default access mode for variables in a struct?
Why sometimes is useful to set a pointer to NULL?
200
Chapter 20. Linked Data Structures
Code 20.2: Linked list first example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 s t r u c t Node {
5
i n t value ;
6
Node * n e x t ;
7 };
8
9 i n t main ( ) {
10
Node * one = new Node ;
11
one −> n e x t = NULL ;
12
one −> v a l u e = 1 ;
13
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Node * two = new Node ;
15
two −> n e x t =NULL ;
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two −> v a l u e = 5 ;
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one −> n e x t = two ;
18
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Node * t h r e e = new Node ;
20
t h r e e −> n e x t =NULL ;
21
t h r e e −> v a l u e = 6 ;
22
two −> n e x t = t h r e e ;
23
24
Node * v i s i t N o d e s = one ;
25
w h i l e ( v i s i t N o d e s ! = NULL) {
26
c o u t << v i s i t N o d e s −> v a l u e << " " ;
27
v i s i t N o d e s = v i s i t N o d e s −> n e x t ;
28
} / / end w h i l e
29 }
20.2 Linked Lists using Classes
20.2
201
Linked Lists using Classes
Next we extend our discussion to include classes, and add some more components to each node.
Each Node will now be an object of a class.
Code 20.3: Linked list example using classes
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 c l a s s Node {
5 private :
6
i n t value ;
7
Node * n e x t ;
8 public :
9
Node ( ) {}
10
Node ( i n t v , Node * n ) : v a l u e ( v ) , n e x t ( n ) {}
11
i n t getValue ( ) const { r e t u r n value ;}
12
Node * g e t N e x t ( ) c o n s t { r e t u r n n e x t ; }
13
void setValue ( i n t v ) { value = v ;}
14
v o i d s e t N e x t ( Node * n ) { n e x t = n ; }
15 } ;
16
17 i n t main ( ) {
18
Node * one = new Node ( 1 , NULL ) ;
19
Node * two = new Node ( 5 , NULL ) ;
20
Node * t h r e e = new Node ( 6 , NULL ) ;
21
22
one −> s e t N e x t ( two ) ;
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two −> s e t N e x t ( t h r e e ) ;
24
25
Node * v i s i t N o d e s = one ;
26
w h i l e ( v i s i t N o d e s ! = NULL) {
27
c o u t << v i s i t N o d e s −> g e t V a l u e ( ) << " " ;
28
v i s i t N o d e s = v i s i t N o d e s −> g e t N e x t ( ) ;
29
} / / end w h i l e
30 }
Do we need the default constructor for class Node?
Chapter 20. Linked Data Structures
202
20.3
Adding and Removing Nodes
Code 20.4: Adding Nodes at the beginning of list
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# include <iostream >
u s i n g namespace s t d ;
c l a s s Node {
private :
i n t value ;
Node * n e x t ;
public :
Node ( i n t v , Node * n ) : v a l u e ( v ) , n e x t ( n ) {}
i n t getValue ( ) const { r e t u r n value ;}
Node * g e t N e x t ( ) c o n s t { r e t u r n n e x t ; }
void setValue ( i n t v ) { value = v ;}
v o i d s e t N e x t ( Node * n ) { n e x t = n ; }
};
t y p e d e f Node * N o d e P o i n t e r ;
v o i d p r i n t L i s t ( Node * h ) {
c o u t << " L i s t c o n t e n t : " ;
Node * v i s i t N o d e s = h ;
w h i l e ( v i s i t N o d e s ! = NULL) {
c o u t << v i s i t N o d e s −> g e t V a l u e ( ) << " " ;
v i s i t N o d e s = v i s i t N o d e s −> g e t N e x t ( ) ;
} / / end w h i l e
c o u t << e n d l ;
} / / end p r i n t L i s t ( )
v o i d i n s e r t H e a d ( N o d e P o i n t e r &h , i n t v ) {
h = new Node ( v , h ) ;
}
i n t main ( ) {
Node * h e a d = NULL ;
p r i n t L i s t ( head ) ;
i n s e r t H e a d ( head , 6 ) ;
p r i n t L i s t ( head ) ;
i n s e r t H e a d ( head , 5 ) ;
p r i n t L i s t ( head ) ;
i n s e r t H e a d ( head , 1 ) ;
p r i n t L i s t ( head ) ;
}
20.3 Adding and Removing Nodes
203
Add a function insert(NodePointer &after, int v) to the program above which adds a new
Node with value = v after the given node. Test the function from main();
Add a function remove(NodePointer &after) to the program above which removes the
given node. Test the function from main();
Add a function find(int key) to the program above which searches the linked list for a
given key value. The function will return true if the key is found and false otherwise.
21. Exception Handling
21.1
Basic Exception Handling
Exception handling is typically used to deal with unexpected errors that may occur during the
execution of the program. This mechanism allows us to detect any errors and have an action plan to
deal with them. Below we start with a very simple code.
Code 21.1: A simple example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t friends = 0;
6
d o u b l e money = 0 . 0 ;
7
8
c o u t << "How many f r i e n d s do you h a v e ? " ;
9
c i n >> f r i e n d s ;
10
c o u t << "How much money do you h a v e ? " ;
11
c i n >> money ;
12
13
d o u b l e a v e r a g e = money / f r i e n d s ;
14
c o u t << " Each f r i e n d w i l l g e t $ " << a v e r a g e ;
15
return 0;
16 }
Under which circumstances we will get an error and how we can deal with it?
206
Chapter 21. Exception Handling
Code 21.2: Dealing with error example
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t f r i e n d s =0;
6
d o u b l e money = 0 . 0 , a v e r a g e = 0 . 0 ;
7
8
c o u t << "How many f r i e n d s do you h a v e ? " ;
9
c i n >> f r i e n d s ;
10
c o u t << "How much money do you h a v e ? " ;
11
c i n >> money ;
12
13
i f ( f r i e n d s <= 0 ) {
14
c o u t << " You n e e d t o f i n d a f r i e n d . " << e n d l ;
15
}
16
else {
17
a v e r a g e = money / f r i e n d s ;
18
c o u t << " Each f r i e n d w i l l g e t $ " << a v e r a g e ;
19
}
20
return 0;
21 }
The potential error in the example above is easily predictable, so we can handle it in a simple way
as we did. We will use the same scenario to illustrate the exception handling mechanism in C++.
This use is not necessary in this example but is a good first example to explain how it works.
21.1 Basic Exception Handling
207
Code 21.3: Using try and catch blocks
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t f r i e n d s =0;
6
d o u b l e money = 0 . 0 , a v e r a g e = 0 . 0 ;
7
8
try {
9
c o u t << "How many f r i e n d s do you h a v e ? " ;
10
c i n >> f r i e n d s ;
11
c o u t << "How much money do you h a v e ? " ;
12
c i n >> money ;
13
14
i f ( f r i e n d s <= 0 )
15
t h r o w money ;
16
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a v e r a g e = money / f r i e n d s ;
18
c o u t << " Each f r i e n d w i l l g e t $ " << a v e r a g e ;
19
}
20
21
catch ( double e ){
22
c o u t << " $ " << e ;
23
c o u t << " w i l l n o t make you happy i f you h a v e no f r i e n d s . " ;
24
}
25
return 0;
26 }
Chapter 21. Exception Handling
208
21.2
Multiple Throws and Catches
Code 21.4: From book. Using multiple try and catch blocks
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 c l a s s NegativeNumber {
5 public :
6
NegativeNumber ( ) { } ;
7
N e g a t i v e N u m b e r ( s t r i n g t h e M e s s a g e ) : m e s s a g e ( t h e M e s s a g e ) {}
8
s t r i n g getMessage ( ) c o n s t { r e t u r n message ; }
9 private :
10
s t r i n g message ;
11 } ;
12 c l a s s D i v i d e B y Z e r o { } ;
13
14 i n t main ( ) {
15
int pencils , erasers ;
16
d o u b l e ppe ;
17
try {
18
c o u t << "How many p e n c i l s do you h a v e ? \ n " ;
19
c i n >> p e n c i l s ;
20
i f ( p e n c i l s < 0)
21
throw NegativeNumber ( " p e n c i l s " ) ;
22
c o u t << "How many e r a s e r s do you h a v e ? \ n " ;
23
c i n >> e r a s e r s ;
24
i f ( e r a s e r s < 0)
25
throw NegativeNumber ( " e r a s e r s " ) ;
26
i f ( e r a s e r s !=0)
27
ppe = p e n c i l s / ( d o u b l e ) e r a s e r s ;
28
else
29
throw DivideByZero ( ) ;
30
c o u t << " Each e r a s e r must l a s t t h r o u g h "
31
<< ppe << " p e n c i l s . \ n " ;
32
}
33
c a t c h ( NegativeNumber e ){
34
c o u t << " C a n n o t h a v e a n e g a t i v e number o f "
35
<< e . g e t M e s s a g e ( ) << e n d l ;
36
}
37
c a t c h ( DivideByZero ){
38
c o u t << "Do n o t make any m i s t a k e s . \ n " ;
39
}
40
catch ( . . . ) {
41
c o u t << " S o m e t h i n g went wrong . " << e n d l ;
42
}
43
c o u t << " End o f p r o g r a m . \ n " ;
44
return 0;
45 }
21.3 Throwing an Exception in a Function
21.3
Throwing an Exception in a Function
Code 21.5: From book. Throwing an exception in a function.
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# include <iostream >
# include < cstdlib >
u s i n g namespace s t d ;
c l a s s DivideByZero {};
double s a f e D i v i d e ( i n t top , i n t bottom ) throw ( DivideByZero ) ;
i n t main ( ) {
i n t numerator , denominator ;
double q u o t i e n t ;
c o u t << " E n t e r n u m e r a t o r : \ n " ;
c i n >> n u m e r a t o r ;
c o u t << " E n t e r d e n o m i n a t o r : \ n " ;
c i n >> d e n o m i n a t o r ;
try {
q u o t i e n t = safeDivide ( numerator , denominator ) ;
}
c a t c h ( DivideByZero ){
c o u t << " E r r o r . D i v i s i o n by Z e r o . \ n " ;
exit (0);
}
c o u t << " R e s u l t
= " << q u o t i e n t << e n d l ;
c o u t << " End o f p r o g r a m . \ n " ;
return 0;
}
double s a f e D i v i d e ( i n t top , i n t bottom ) throw ( DivideByZero ){
i f ( b o t t o m == 0 )
throw DivideByZero ( ) ;
r e t u r n top / ( double ) bottom ;
}
209
22. Standard Template Library
The Standard Template Library is a collection of C++ template classes that allows us to create
commonly used data structures such as lists, vectors, stacks, queues, etc. Since these classes (ofter
referred to as container classes) are often used, they are part of the C++ standard and can be used
with any of the C++ installations.
22.1
Iterators
A data structure is created to store and access information in an organized and efficient manner.
One way of access and use this information is by using iterators. Iterators allows us to cycle through
the data to obtain any necessary information stored in the data structure.
Previously we discussed Linked Lists. We used pointers to visit each node (or a subset of nodes) as
needed for various operations on a Linked List. The pointer in this case would be one example of
an iterator.
212
22.2
Chapter 22. Standard Template Library
Vectors
Vectors are very similar to arrays. The main difference is the ability of vectors to change size during
the execution of a program which is not true for arrays. Vectors are created by using a template
from the STL. An iterator is available to allow access and manipulation of data in a given vector.
The example below tests some of the basic functions of a vector data structure.
Code 22.1: From book. Vector example
1 # include <iostream >
2 # include <vector >
3 u s i n g namespace s t d ;
4
5 i n t main ( ) {
6
vector <int > container ;
7
8
f o r ( i n t i = 1 ; i <= 4 ; i ++)
9
c o n t a i n e r . push_back ( i ) ;
10
11
c o u t << " Here i s what i s i n t h e c o n t a i n e r : \ n " ;
12
vector <int >:: i t e r a t o r p ;
13
f o r ( p = c o n t a i n e r . b e g i n ( ) ; p ! = c o n t a i n e r . end ( ) ; p ++)
14
c o u t << * p << " " ;
15
c o u t << e n d l ;
16
17
c o u t << " S e t t i n g e n t r i e s t o 0 : \ n " ;
18
19
f o r ( p = c o n t a i n e r . b e g i n ( ) ; p ! = c o n t a i n e r . end ( ) ; p ++)
20
*p = 0 ;
21
22
c o u t << " C o n t a i n e r now c o n t a i n s : \ n " ;
23
f o r ( p = c o n t a i n e r . b e g i n ( ) ; p ! = c o n t a i n e r . end ( ) ; p ++)
24
c o u t << * p << " " ;
25
c o u t << e n d l ;
26
27
return 0;
28 }
22.3 Queue Iterator Example
22.3
213
Queue Iterator Example
The following example taken from your book shows an example of creating and using an iterator
for a queue class. All separate content can be merged as is into one file or can be saved into separate
files by adding the appropriate headers. The entire merged code can be obtained by following the
link below:
<— Get code here.
Code 22.2: From book. Node class declaration with inline definitions
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13
t e m p l a t e < c l a s s T>
c l a s s Node {
public :
Node ( T t h e D a t a , Node<T> * t h e L i n k ) : d a t a ( t h e D a t a ) , l i n k ( t h e L i n k ) {}
Node<T> * g e t L i n k ( ) c o n s t { r e t u r n l i n k ; }
c o n s t T& g e t D a t a ( ) c o n s t { r e t u r n d a t a ; }
v o i d s e t D a t a ( c o n s t T& t h e D a t a ) { d a t a = t h e D a t a ; }
v o i d s e t L i n k ( Node<T> * p o i n t e r ) { l i n k = p o i n t e r ; }
private :
T data ;
Node<T> * l i n k ;
};
Code 22.3: From book. List Iterator class declaration with inline definitions
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t e m p l a t e < c l a s s T>
class ListIterator {
public :
L i s t I t e r a t o r ( ) : c u r r e n t (NULL) { }
L i s t I t e r a t o r ( Node<T> * i n i t i a l ) : c u r r e n t ( i n i t i a l ) { }
c o n s t T& o p e r a t o r * ( ) c o n s t { r e t u r n c u r r e n t −> g e t D a t a ( ) ; }
L i s t I t e r a t o r& o p e r a t o r ++(){
c u r r e n t = c u r r e n t −> g e t L i n k ( ) ;
return * this ;
}
L i s t I t e r a t o r & o p e r a t o r ++( i n t ) {
ListIterator startVersion ( current );
c u r r e n t = c u r r e n t −> g e t L i n k ( ) ;
return startVersion ;
}
b o o l o p e r a t o r ==( c o n s t L i s t I t e r a t o r r i g h t S i d e ) c o n s t {
r e t u r n ( c u r r e n t == r i g h t S i d e . c u r r e n t ) ;
}
Chapter 22. Standard Template Library
214
22
23
24
25
26
27
28
29
bool o p e r a t o r !=( const L i s t I t e r a t o r r i g h t S i d e ) const {
r e t u r n ( c u r r e n t != r i g h t S i d e . c u r r e n t ) ;
}
private :
Node<T> * c u r r e n t ;
};
Code 22.4: From book. Class Queue declaration with some inline definitions
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t e m p l a t e < c l a s s T>
c l a s s Queue {
public :
t y p e d e f L i s t I t e r a t o r <T> I t e r a t o r ;
Queue ( ) ;
Queue ( c o n s t Queue <T>& aQueue ) ;
Queue <T>& o p e r a t o r = ( c o n s t Queue <T>& r i g h t S i d e ) ;
v i r t u a l ~Queue ( ) ;
v o i d add ( T i t e m ) ;
T remove ( ) ;
bool isEmpty ( ) c o n s t ;
I t e r a t o r begin ( ) const { r e t u r n I t e r a t o r ( f r o n t ) ; }
I t e r a t o r end ( ) c o n s t { r e t u r n I t e r a t o r ( ) ; }
private :
Node<T> * f r o n t ;
Node<T> * b a c k ;
};
Code 22.5: From book. Main function
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7
8
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13
14
i n t main ( ) {
char next , ans ;
do {
Queue < c h a r > q ;
c o u t << " E n t e r a l i n e o f t e x t : \ n " ;
cin . get ( next ) ;
while ( n e x t != ’ \ n ’ ){
q . add ( n e x t ) ;
cin . get ( next ) ;
}
c o u t << " You e n t e r e d : \ n " ;
Queue < c h a r > : : I t e r a t o r i ;
22.3 Queue Iterator Example
15
f o r ( i =q . b e g i n ( ) ; i ! = q . end ( ) ; i ++)
16
c o u t << * i ;
17
c o u t << e n d l ;
18
19
20
c o u t << " Again ? ( y / n ) : " ;
21
c i n >> a n s ;
22
cin . ignore (10000 , ’ \ n ’ ) ;
23
24
} w h i l e ( a n s ! = ’ n ’ && a n s ! = ’N ’ ) ;
25
26
return 0;
27 }
Code 22.6: From book. Remaining function definitions from class Queue
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t e m p l a t e < c l a s s T>
Queue <T > : : Queue ( ) : f r o n t (NULL ) , b a c k (NULL) { }
t e m p l a t e < c l a s s T>
Queue <T > : : Queue ( c o n s t Queue <T>& aQueue ) {
i f ( aQueue . i s E m p t y ( ) ) {
f r o n t = b a c k = NULL ;
}
else {
Node<T> * temp = aQueue . f r o n t ;
b a c k = new Node<T> ( temp −> g e t D a t a ( ) , NULL ) ;
f r o n t = back ;
temp = temp −> g e t L i n k ( ) ;
w h i l e ( temp ! =NULL) {
back −> s e t L i n k ( new Node<T> ( temp −> g e t D a t a ( ) , NULL ) ) ;
b a c k = back −> g e t L i n k ( ) ;
temp = temp −> g e t L i n k ( ) ;
}
}
}
t e m p l a t e < c l a s s T>
Queue <T>& Queue <T > : : o p e r a t o r = ( c o n s t Queue <T>& r i g h t S i d e ) {
i f ( f r o n t == r i g h t S i d e . f r o n t )
return * this ;
else {
T next ;
while ( ! isEmpty ( ) )
n e x t = remove ( ) ;
}
i f ( r i g h t S i d e . isEmpty ( ) ) {
f r o n t = back = n u l l p t r ;
215
Chapter 22. Standard Template Library
216
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return * this ;
}
else {
Node<T> * temp = r i g h t S i d e . f r o n t ;
b a c k = new Node<T> ( temp −> g e t D a t a ( ) , n u l l p t r ) ;
f r o n t = back ;
temp = temp −> g e t L i n k ( ) ;
w h i l e ( temp ! = n u l l p t r )
{
back −> s e t L i n k (
new Node<T> ( temp −> g e t D a t a ( ) , n u l l p t r ) ) ;
b a c k = back −> g e t L i n k ( ) ;
temp = temp −> g e t L i n k ( ) ;
}
return * this ;
}
}
t e m p l a t e < c l a s s T>
Queue <T > : : ~Queue ( ) {
T next ;
while ( ! isEmpty ( ) )
n e x t = remove ( ) ;
}
t e m p l a t e < c l a s s T>
v o i d Queue <T > : : add ( T i t e m ) {
i f ( isEmpty ( ) )
f r o n t = b a c k = new Node<T> ( i t e m , n u l l p t r ) ;
else
{
back −> s e t L i n k ( new Node<T> ( i t e m , n u l l p t r ) ) ;
b a c k = back −> g e t L i n k ( ) ;
}
}
t e m p l a t e < c l a s s T>
T Queue <T > : : remove ( ) {
i f ( isEmpty ( ) )
{
c o u t << " E r r o r : Removing an i t e m from an empty q u e u e . \ n " ;
exit (1);
}
T r e s u l t = f r o n t −> g e t D a t a ( ) ;
Node<T> * d i s c a r d ;
discard = front ;
f r o n t = f r o n t −> g e t L i n k ( ) ;
i f ( f r o n t == n u l l p t r )
back = n u l l p t r ;
22.3 Queue Iterator Example
82
delete discard ;
83
return result ;
84 }
85
86 t e m p l a t e < c l a s s T>
87 b o o l Queue <T > : : i s E m p t y ( ) c o n s t {
88
r e t u r n ( b a c k == NULL ) ;
89 }
217
III
Part Three - Other Topics
23
File Processing . . . . . . . . . . . . . . . . . . . . . 221
A
Answers to Exercises . . . . . . . . . . . . . . . . 225
Index . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 229
23. File Processing
23.1
Stream Objects
The output generated by the C++ program will be lost unless is stored somewhere in permanent
memory. In this section we will discuss how to store and retrieve data to and from a file.
Code 23.1: Creating a new file in the current workspace.
1 # include <fstream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
ofstream myOutputFile ( " output . t x t " ) ;
6
7
m y O u t p u t F i l e << "MAC 101 " << e n d l ;
8
m y O u t p u t F i l e << " Computer S c i e n c e " << e n d l ;
9
myOutputFile . close ( ) ;
10
11
return 0;
12 }
Note: File stream objects support the same function calls as the cin/cout objects.
Change the output text and run the program again. What do you notice?
Chapter 23. File Processing
222
Code 23.2: Creating a new file in a new, specific location.
1 # include <fstream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
ofstream myOutputFile ( " c : \ \ TestFolder \ \ output2 . t x t " ) ;
6
7
m y O u t p u t F i l e << "MAC 101 " << e n d l ;
8
m y O u t p u t F i l e << " Computer S c i e n c e " << e n d l ;
9
myOutputFile . close ( ) ;
10
11
return 0;
12 }
Why do we need to use double slash (\\) in the file path?
Example: We can use pre-defined functions to open a file, check the existence of a file and many
other related operations.
Code 23.3: Open a file example.
1 include <fstream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i f s t r e a m myOutputFile ;
6
m y O u t p u t F i l e . open ( " o u t p u t . t x t " ) ;
7
8
i f ( myOutputFile . f a i l ( ) ) {
9
c o u t << " C a n n o t open f i l e ! ! ! " ;
10
r e t u r n −1;
11
}
12
13
c o u t << " The f i l e i s open . " ;
14
myOutputFile . close ( ) ;
15
return 0;
16 }
23.1 Stream Objects
223
Example: Read content from a file one page at a time and display on the console window.
Code 23.4: Read file example.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
# include <iostream >
# include <fstream >
# include <string >
u s i n g namespace s t d ;
i n t main ( ) {
s t r i n g fileName , l i n e O f T e x t ;
c o u t << " E n t e r a f i l e name : " ;
g e t l i n e ( cin , fileName ) ;
i f s t r e a m myFile ( fileName ) ;
i f ( ! myFile ) {
c o u t << f i l e N a m e << " c o u l d n o t be o p e n e d . " ;
r e t u r n −1;
}
while ( t r u e ) {
char c = ’a ’ ;
f o r ( i n t i = 1 ; i <= 24 && ! m y F i l e . e o f ( ) ; i ++) {
g e t l i n e ( myFile , l i n e O f T e x t ) ;
c o u t << l i n e O f T e x t << e n d l ;
}
i f ( myFile . eof ( ) )
break ;
c o u t << " E n t e r ’Q ’ t o q u i t . " ;
g e t l i n e ( cin , lineOfText ) ;
c = lineOfText [ 0 ] ;
i f ( c == ’Q ’ | | c == ’ q ’ )
break ;
}
return 0;
}
a) Create a folder PracticeFolder in the c: directory of your computer.
b) Modify the C++ program from above to create a new file “numbers.txt”.
c) Write in the file the first 100 positive integers, each value in a new line.
d) Use the program to output the content of the “numbers.txt” file 10 numbers at a time.
Chapter 23. File Processing
224
Example: Append text at the end of a file.
Code 23.5: Append text example
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
# include <iostream >
# include <fstream >
# include <string >
u s i n g namespace s t d ;
i n t main ( ) {
s t r i n g someText ;
o f s t r e a m m y F i l e ( " r e c o r d s . t x t " , i o s : : app ) ;
i f ( ! myFile ) {
c e r r << " F i l e c o u l d n o t be o p e n e d . " << e n d l ;
exit (1);
}
c o u t << " E n t e r some t e x t o r t y p e ’ e x i t ’ t o s t o p : " << e n d l ;
w h i l e ( g e t l i n e ( c i n , someText ) && someText ! = " e x i t " )
m y F i l e << someText << e n d l ;
return 0;
}
Note: Besides ios::app, there several other available fstream modes.
Write a C++ program that allows the user to search a file “MyText.txt” located in the
current workspace for any word (String). The program should print the result of the
search. In the event the word is found the program should indicate the line where it was
found in the text file.
Desired output format sample 1:
Enter the word you are looking for: hello
The word hello was not found.
Desired output format sample 2:
Enter the word you are looking for: hello
The word hello was found in line 3 of the text.
A. Answers to Exercises
A.1
Chapter 1
→ Answer to question 2
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( )
5 {
6
c o u t << " T h i s i s t h e f i r s t l i n e . " << e n d l << e n d l ;
7
c o u t << " T h i s i s t h e s e c o n d l i n e . " << e n d l ;
8
9
return 0;
10 }
→ Answer to question 4
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
c o u t << " * \ n * * \ n * * * \ n **** " << e n d l ;
6
return 0;
7 }
Chapter A. Answers to Exercises
226
→ Answer to question 6
Write a C++ program that prompts the user to input their age, and then outputs a message
stating their age. The program should use proper grammar and punctuation to form a complete sentence. For example, if the user enters "25", the program should output "You are 25
years old."
Your program should display a prompt asking the user to enter their age, and then read in the
age from the user using the appropriate input method. Finally, the program should output the
user’s age in a message that includes the number of years and proper punctuation.
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t age ;
6
c o u t << " E n t e r y o u r a g e : " ;
7
c i n >> a g e ;
8
c o u t << " You a r e " << a g e << " y e a r s o l d . " << e n d l ;
9
return 0;
10 }
→ Item 2
A.2
Chapter 3
→ Answer to question 1
1. variable: A variable is a named storage location in computer memory that holds a
value of a particular data type. It is a symbolic representation of a memory location
that can hold different values at different times during the execution of a program.
2. identifier: An identifier is a name given to a variable, function, class, or any other
user-defined item in a program. An identifier must follow certain naming rules and
conventions and should be unique within its scope.
3. keyword: A keyword is a reserved word that has a special meaning in the programming
language and cannot be used as an identifier. Keywords are used to define the syntax and
structure of the language, and they have predefined functions that cannot be changed by
the programmer.
4. statement: A statement is a unit of code that performs a specific action in a program.
It can be a declaration, an assignment, a function call, a control statement, or any other
operation that can be performed in the language.
5. declaring a variable: Declaring a variable is the process of defining a named storage
location in memory with a specific data type. It involves specifying the variable name,
the data type, and optionally an initial value.
6. initializing a variable: Initializing a variable is the process of assigning an initial value
to a declared variable. It can be done at the time of declaration or later in the program.
7. assignment statement: An assignment statement is a statement that assigns a value to
a variable. It involves using the assignment operator ’=’ to assign a value to the variable
on the left-hand side of the operator.
A.2 Chapter 3
227
→ Answer to question 2
1. All variables must be declared before being used. (True - False)
True. This means that their type and name must be specified in a declaration statement
before they can be used in any other statements.
2. C++ considers the variable number and NUMBER to be identical. (True - False)
False. In C++, variable names are case sensitive, which means that "number" and
"NUMBER" are two different identifiers and not identical.
3. The arithmetic operators *, /, +, and – have the same level of precedence. (True - False)
False. The arithmetic operators in C++ have different levels of precedence, which
determine the order in which they are evaluated. The * and / operators have a higher
precedence than + and - operators.
4. The statement cout « “a = 5;” ; is a typical assignment statement. (True - False)
False. The statement "cout « “a = 5;” ;" is an output statement that writes the value of
the string "a = 5;" to the console. An assignment statement assigns a value to a variable,
for example: "a = 5;".
5. The statements n +=2; and n = n+2; have the exact same outcome. (True - False)
True. The statements "n += 2;" and "n = n + 2;" are equivalent and have the same
outcome. The += operator is a compound assignment operator that adds the value on
the right-hand side to the variable on the left-hand side and then assigns the result to
the left-hand side variable.
6. The size of the int data type is guaranteed to be 4 bytes on all platforms. (True - False)
False. The size of the int data type is not guaranteed to be 4 bytes on all platforms. The
C++ standard only specifies that an int must be able to represent at least the range of
values from -32767 to 32767, which requires 2 bytes.
7. The double data type can hold larger values than the float data type. (True - False)
True. The double data type can hold larger values than the float data type because it
uses 8 bytes to represent a floating-point number, while the float data type uses 4 bytes.
8. C++ has a built-in data type for representing Boolean values. (True - False)
True. C++ has a built-in data type called bool that represents Boolean values, which
can have the value true or false.
9. The "sizeof" operator in C++ returns the number of bytes occupied by a variable. (True
- False)
True. For example, the expression "sizeof(int)" returns the number of bytes occupied
by an int variable on the current platform.
→ Answer to question 5
A variable that can have values only in the range 0 to 65535 is a two-byte unsigned integer.
An unsigned integer is a non-negative integer that can have values from 0 to a certain
maximum value determined by the number of bytes used to store the value. A two-byte
unsigned integer can store values in the range of 0 to 216 − 1, which is equivalent to 0 to
65535. Therefore, option (d) "two-byte unsigned integer" is the correct answer.
→ Answer to question 7
The largest unsigned integer that can be represented with 32 bits is 232 − 1, which is equal to
4,294,967,295.
The largest unsigned integer that can be represented with 64 bits is 264 − 1, which is equal to
Chapter A. Answers to Exercises
228
18,446,744,073,709,551,615.
→ Answer to question 10
1 # include <iostream >
2 u s i n g namespace s t d ;
3
4 i n t main ( ) {
5
i n t x = 0;
6
7
/ / U s i n g t h e + o p e r a t o r and t h e = o p e r a t o r
8
x = x + 1;
9
c o u t << " x = " << x << e n d l ;
10
11
/ / U s i n g t h e += o p e r a t o r
12
x += 1 ;
13
c o u t << " x = " << x << e n d l ;
14
15
/ / U s i n g t h e p o s t f i x ++ o p e r a t o r
16
x ++;
17
c o u t << " x = " << x << e n d l ;
18
19
/ / U s i n g t h e p r e f i x ++ o p e r a t o r
20
++x ;
21
c o u t << " x = " << x << e n d l ;
22
23
return 0;
24 }
→ Answer to question ??
A.3
Chapter 3
→ Answer to question A.3
→ Item 2
→ Item 3
Index
if and if-else Statements, 41
Abstract Classes, 181
Adding and Removing Nodes, 192
Addition and Subtraction of Numbers at Different Bases, 20
Arithmetic Operations, 29
Array Size, 101
Arrays and Pointer Arithmetic, 112
Arrays and Pointers, 150
Arrays of Structures, 118
Background, 183
Basic Exception Handling, 195
C++ Loops. The while and do. . . while Statement., 55
C++ Syntax Tokens, 25
C-style String Functions, 127
Characters, Strings and Arrays of Strings, 104
Class Composition, 147
Class Templates, 187
Classes, 122
Constant Objects, 145
Constructors, 140
Conversion Between Binary, Octal and Hexadecimal, 19
Converting Binary, Octal and Hexadecimal to
Decimal, 15
Converting Decimal Numbers to Other Bases,
17
Default and Static Variables, 90
Default Function Arguments, 78
Destructors, 142
Function Overloading, 79
Function Templates, 185
Getting Started with C++, 11
How C++ Stores Text?, 125
Inheritance, 167
Inheritance and Constructors, 170
Inheriting Functionality, 172
Initializing Arrays, 98
Iterators, 201
Linked Lists, 189
Linked Lists using Classes, 191
Local and Global Variables, 89
Logical Operators, 46
Member Initializers, 146
More on Recursion, 159
Multi-Dimensional Arrays, 105
Multilevel Inheritance, 175
Multiple Inheritance, 174
Multiple Throws and Catches, 198
Objects, 121
Operator Overloading, 153
230
Passing a Parameter by Value or by Reference,
76
Passing Arrays to Functions, 102
Passing Structures to Functions, 119
Pointers and Some Special Operators, 150
Pointers Revisited, 149
Polymorphism and Virtual Functions, 177
Practice Questions 1, 13
Practice Questions 2, 22
Practice Questions 3, 32, 49
Practice Questions 5, 61
Practice Questions 6, 80
Practice Questions 7, 93, 162
Practice Questions 8, 106
Pre-defined Functions, 91
Primitive Data Types, 27
Queue Iterator Example, 203
Recursive Functions, 155
Relational and Comparison Operators, 41
Separating Content in Different Files, 143
Sorting Algorithms, 133
Storing Information in the Computer, 15
Stream Objects, 211
Structure Composition, 117
The <string> Class, 128
The break and continue Statements, 60
The for loop, 57
The switch Statement, 44
The First Example, 122
The Nested if-else Statements, 44
The this Keyword, 152
Throwing an Exception in a Function, 199
Vectors, 202
What are Arrays, 97
What are Functions?, 71
What are Pointers?, 111
What are Structures?, 115
What is Computer Science?, 9
What is Programming?, 10
INDEX