A First Book of C++
Chapter 1
Getting Started
Objectives
• In this chapter, you will learn about:
– Introduction to Programming
– Function and Class Names
– The cout Object
– Programming Style
– Common Programming Errors
– Software Development
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Introduction to Programming
• Computer program
– Data and instructions used to operate a computer
• Programming
– Writing computer program in a language that the
computer can respond to and that other programmers
can understand
• Programming language
– Set of instructions, data, and rules used to construct a
program
• High-level languages
• Low-level languages
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Introduction to Programming (cont’d.)
• Procedural language
– Instructions are used to create self-contained units
(procedures)
– Procedures accept data as input and transform data
to produce a specific result as an output
– Initially, high-level programming languages were
predominately procedural
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Introduction to Programming (cont’d.)
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Introduction to Programming (cont’d.)
• Object-oriented languages
– Program must define objects that it is manipulating
– Such definitions include:
• The general characteristics of objects
• Specific operations to manipulate objects
• C++ is an object-oriented language
– Has procedures and objects
– Supports code reuse
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Introduction to Programming (cont’d.)
• C++ began as extension to C
– C is a procedural language developed in the 1970s at
AT&T Bell Laboratories
• In early 1980s, Bjarne Stroustrup (also at AT&T)
used his background in simulation languages to
develop C++
• Object-orientation and other procedural
improvements were combined with existing C
language features to form C++
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Algorithms and Procedures
• Before writing a program, a programmer must
clearly understand:
– What data is to be used
– The desired result
– The procedure needed to produce this result
• The procedure is referred to as an algorithm
– Step-by-step sequence of instructions describing how
to perform a computation
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Algorithms and Procedures (cont’d.)
• Assume that a program must calculate the sum of all
whole numbers from 1 through 100
• A computer:
– Cannot respond to heuristic command: “Add the
numbers from 1 - 100”
– Is an algorithm-responding machine and not a
heuristic-responding machine
• Several methods or algorithms can be used to find
the required sum
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Classes and Objects
• Data object
– Set of values packaged as single unit
• Class
– Set of objects with similar attributes
• General concept of object-oriented programming is
difference between an object and the larger set of
which it is a member (class)
• A red, Ford Taurus sedan is an instance, or object,
of a general class of automobiles
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Program Translation
• C++ source program
– Set of instructions written in C++ language
• Machine language
– Internal computer language
– Consists of a series of 1s and 0s
• Source program cannot be executed until it is
translated into machine language
– Interpreted language translates one statement at a
time (BASIC – Perl)
– Compiled language translates all statements together
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Program Translation (cont'd.)
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Program Translation (cont'd.)
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Function and Class Names
• Modular programs
– Segments arranged in logical order to form an
integrated unit
• Module
– Segments of modular program
• Function: Name of a C++ procedure
– Composed of sequence of C++ instructions
– Function interface is its inputs and results
– Method of converting input to results is encapsulated
and hidden within function
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Function and Class Names (cont'd.)
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Function and Class Names (cont'd.)
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Function and Class Names (cont'd.)
• An important requirement for designing a good
function or class is giving it a name that conveys
some idea of what the function or class does.
• The names allowed for functions and classes are
also used to name other elements of the C++
language and are collectively referred to as
identifiers.
• Identifiers can be made up of any combination of
letters, digits, and underscores ( _ ) selected
according to the following rules:
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Function and Class Names (cont'd.)
• Identifiers
– Names that convey an idea of the purpose of function
or class
• Identifier composition rules
– First character must be a letter or underscore
– Only letter, digit, or underscore may follow
– Blank spaces aren’t allowed
– Separate words in a multiple-word identifier are
indicated by capitalizing the first letter of one or more of
the words
– Should be a mnemonic – Maximum of 1024 characters
– Cannot be one of the keywords listed in Table 1.1
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Function and Class Names (cont'd.)
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Function and Class Names (cont'd.)
• Examples of valid identifiers:
grosspay
taxCalc
addNums
degToRad
multByTwo
salesTax
netPay
bessel
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Function and Class Names (cont'd.)
• Examples of invalid identifiers:
4ab3
(begins with a number)
e*6
(contains a special character)
while
(is a keyword)
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Function and Class Names (cont'd.)
• In addition to conforming to C++’s identifier rules, a
C++ function name must always be followed by
parentheses.
• Function names can also consist of mixed
uppercase and lowercase letters, as in
locateMaximum().
• C++ is a case-sensitive language, meaning the
compiler distinguishes between uppercase and
lowercase letters.
• Therefore, in C++, the names TOTAL, total, and
TotaL are three different identifiers.
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The main() Function
• Each C+ program must have one and only one
function named main
• Called a driver function because it drives the other
modules
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The main() Function (cont'd.)
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The main() Function (cont'd.)
• First line of function is called header line
– What type of data, if any, is returned from function
– The name of function
– What type of data, if any, is sent into function
• Data transmitted into function at runtime are referred
to as arguments of function
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The main() Function (cont'd.)
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The cout Object
• The cout object sends data to the standard output
display device
– The display device is usually a video screen
– Name derived from Console OUTput and pronounced
“see out”
• Data is passed to cout by the insertion symbol
– cout << “Hello there, World!”;
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The cout Object (cont’d.)
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The cout Object (cont’d.)
• Preprocessor command
– Performs an action before the compiler translates
source code to machine code
– Example: #include <iostream>
– Causes the iostream file to be inserted wherever
the #include command appears
• iostream is part of the C++ standard library
– Included in iostream are two important classes:
• istream: Declarations and methods for data input
• ostream: Declarations and methods for data output
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The cout Object (cont’d.)
• Namespace
– File accessed by compiler when looking for prewritten
classes or functions
• Sample namespace statement:
– using namespace std;
– iostream contained in a namespace called std
– Compiler uses iostream’s cout object from std
whenever cout is referenced
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The cout Object (cont’d.)
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The cout Object (cont’d.)
• Newline escape sequence
– Instructs the display device to move to a new line
– Caused when the characters backslash \ and n are
used together
– Backslash provides an “escape” from the normal
interpretation of the character that follows
• Newline escape sequences can be placed
anywhere within a message to cout
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The cout Object (cont’d.)
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Programming Style
• Every C++ program must contain one and only one
main() function
– Statements included within braces { }
• C++ allows flexibility in format for the word main, the
parentheses ( ), and braces { }
– More than one statement can be put on line
– One statement can be written across lines
• Use formatting for clarity and ease of program
reading
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Programming Style (cont’d.)
• Function name starts in column 1
– Name and parentheses on their own line
• Opening brace of function body on next line
– Aligned with first letter of function name
• Closing brace is last line of function
– Aligned with opening brace
• Standard form highlights the function as a unit
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Programming Style (cont’d.)
• Within function, indent statements 2-3 spaces
– Creates uniform look for similar statement groups
– Good programming practice
• Final program form should be consistent
– Proper format improves program readability and
understandability
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Comments
• Explanatory remarks written within program
– Clarify purpose of the program
– Describe objective of a group of statements
– Explain function of a single line of code
• Computer ignores all comments
– Comments exist only for convenience of reader
• A well-constructed program should be readable and
understandable
– Comments help explain unclear components
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Comments (cont’d.)
• Line comment
– Begins with two slashes(//) and continues to the end
of the line
– Can be written on line by itself or at the end of line
that contains program code
//
this is a line comment
• Block comment
– Multiple-line comment begins with the symbols /*
and ends with the symbols */
/* This is a block comment that
spans
three lines */
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Common Programming Errors
• Omitting parentheses after main()
• Omitting or incorrectly typing the opening brace {
– Opening brace signifies start of function body
• Omitting or incorrectly typing the closing brace }
– Closing brace signifies end of function
• Omitting the semicolon at the end of each statement
• Adding a semicolon after the #include
<iostream> preprocessor command
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Common Programming Errors (cont'd.)
• Misspelling the name of an object or function
– Example: Typing cot instead of cout
• Forgetting to close a string sent to cout with a
double-quote symbol
• Forgetting \n to indicate a new line
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Summary
• A C++ program consists of one or more modules
– One module must be the function main()
– main() is starting point of C++ program
• The simplest C++ program has the form:
#include <iostream>
using namespaces std;
int main()
{
program statements;
return 0;
}
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Summary (cont'd.)
• C++ statements are terminated by a semicolon
• Standard library contains many functions and
classes
– Standard Library provided with C++ compiler
– Includes <iostream> for input and output
• cout object displays text or numeric results
– Stream of characters is sent to cout by:
• Enclosing characters in double quotes
• Using the insertion (“put to”) operator, <<
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Chapter Supplement: Software
Development
• Professional software developers use the software
development procedure
– For understanding the problem to be solved and for
creating an effective, suitable software solution
• Consists of three overlapping phases:
– Development and design
– Documentation
– Maintenance
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Phase I: Development and Design
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Phase II: Documentation
• Every problem solution has five main documents:
– Program description
– Algorithm development and changes
– Well-commented program listing
– Sample test runs
– Users’ manual
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Phase III: Maintenance
• Phase is concerned with:
– Ongoing correction of problems
– Revisions to meet changing needs
– Addition of new features
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Chapter Supplement: Backup
• Not part of the formal design process
• Keeping backup copies of the program at each step
of the programming and debugging process is
critical
• With backup copies, you can recover the last stage
of work with little effort
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