Programming Fundamentals
4-Jan-24
Chapter 1: Introduction to
Computers, Programs, and C++
Sections 1.1 - 1.3, 1.6 - 1.9
Textbooks: Y. Daniel Liang, Introduction to Programming with C++, 3rd Edition
© Copyright 2016 by Pearson Education, Inc. All Rights Reserved.
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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What is a Computer?
A computer consists of a CPU, memory, hard disk,
monitor, and communication devices.
Bus
Storage
Devices
Memory
e.g., Disk, CD,
and Tape
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CPU
Communication
Devices
Input
Devices
Output
Devices
e.g., Modem,
and NIC
e.g., Keyboard,
Mouse
e.g., Monitor,
Printer
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CPU
The central processing unit (CPU) is the brain of a
computer. It retrieves instructions from memory and
executes them. The CPU speed is measured in megahertz
(MHz), with 1 megahertz equaling 1 million pulses per
second. The speed of the CPU has been improved
continuously. If you buy a PC now, you can get an Intel
Core i7 Processor at 3 gigahertz (1 gigahertz is 1000
megahertz).
Bus
Storage
Devices
Memory
e.g., Disk, CD,
and Tape
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CPU
Communication
Devices
Input
Devices
Output
Devices
e.g., Modem,
and NIC
e.g., Keyboard,
Mouse
e.g., Monitor,
Printer
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Memory
Memory is to store data and program instructions for CPU
to execute. A memory unit is an ordered sequence of
bytes, each holds eight bits. A program and its data must
be brought to memory before they can be executed. A
memory byte is never empty, but its initial content may be
meaningless to your program. The current content of a
memory byte is lost whenever new information is placed
in it.
Bus
Storage
Devices
Memory
e.g., Disk, CD,
and Tape
Faculty of Computer Science and Engineering
CPU
Communication
Devices
Input
Devices
Output
Devices
e.g., Modem,
and NIC
e.g., Keyboard,
Mouse
e.g., Monitor,
Printer
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How Data is Stored?
• Data of various kinds are
encoded as a series of bits (zeros
and ones).
• The encoding scheme varies. For
example, character ‘J’ is
represented by 01001010 in one
byte.
• A small number such as 3 can be
stored in a single byte.
• If computer needs to store a
large number that cannot fit into
a single byte, it uses a number of
adjacent bytes.
• A byte is the minimum storage
unit.
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Storage Devices
Memory is volatile, because information is lost when the
power is off. Programs and data are permanently stored
on storage devices and are moved to memory when the
computer actually uses them. There are four main types
of storage devices: Disk drives (hard disks), Solid-state
devices (SSD, Flash), CD drives (CD-R and CD-RW), and
Tape drives.
Bus
Storage
Devices
Memory
e.g., Disk, CD,
and Tape
Faculty of Computer Science and Engineering
CPU
Communication
Devices
Input
Devices
Output
Devices
e.g., Modem,
and NIC
e.g., Keyboard,
Mouse
e.g., Monitor,
Printer
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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Programs
Computer programs, known as software, are instructions
to the computer.
You tell a computer what to do through programs. Without
programs, a computer is an empty machine. Computers do
not understand human languages, so you need to use
computer languages to communicate with them.
Programs are written using programming languages.
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Programming Languages
Machine Language Assembly Language
Machine language is a set of primitive
instructions built into every computer.
The instructions are in the form of
binary code, so you have to enter
binary codes for various instructions.
Program with native machine language
is a tedious process. Moreover, the
programs are highly difficult to read
and modify.
For example, to add two numbers, you
might write an instruction in binary like
this:
1101101010011010
ADD
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High-Level Language
Early computer systems used to punch
the 0’s and 1’s on special cardboard
paper (punch cards)
Imagine making a single mistake and
you have to do it all again! Impractical
e.g., computer designers will agree
what operation the first 4 bits indicate
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Programming Languages
Machine Language Assembly Language
Assembly languages were developed to
make programming a bit easier.
Instead of writing programs in 0’s and
1’s, we write the program in terms of
the desired operation (ADD, SUB,
MOV), the numerical numbers,
memory locations, etc.
High-Level Language
For example, to add two numbers,
you might write an instruction in
assembly code like this:
add
2, 3, result
Since the computer cannot understand
assembly language, a program called
assembler is used to convert assembly
language programs back into machine
code.
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Programming Languages
Machine Language Assembly Language
▪
▪
▪
▪
▪
High-Level Language
There are dozens of computer processor types: INTEL/AMD (found
mostly in PCs, laptops, servers), ARM (found mostly in tablets, phones,
some laptops), MIPS, RISC-V, etc.
Each has a different design→ different machine code → different
assembly language.
Imagine learning different assembly languages to develop a program
that runs on all these different computers. IMPRACTICAL!
Solution: high-level languages written once, and translated to different
assembly languages as needed (one program → many machines)
The high-level languages are English-like and easy to learn and program.
For example, the following is a high-level language statement that
computes the area of a circle with radius 5:
area = 5 * 5 * 3.1416;
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High-Level Languages
Old High-Level Languages:
COBOL (COmmon Business Oriented Language), FORTRAN (FORmula TRANslation),
BASIC (Beginner All-purpose Symbolic Instructional Code), Pascal, Ada, Delphi
Popular High-Level Languages:
• C (used a lot in hardware programming / similar to C++)
• Visual Basic (Basic-like visual language developed by Microsoft)
• C++ (an object-oriented language, based on C)
• Java (a popular object-oriented language, similar to C++)
• C# (a Java-like developed my Microsoft)
• MATLAB (oriented for engineering and scientific applications)
• Python (used widely in data analysis and artificial intelligence )
• JavaScript (front-end/back-end, and mobile development)
• Also: Go, Ruby, Swift, Objective-C, Rust, Scala, Perl
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From High-Level to Machine Code:
Compiling versus Interpretation
• Some programming languages like Python/MATLAB have interpreters that
translate and execute a program line by line as long as they are correct as seen in
Fig. (a). Think of it as being in a conference room, and someone is translating the
speech from English to Arabic as the person speaks.
• C++ needs a compiler that translates the entire source program into a machinelanguage file for execution Fig. (b). All the program must be in machine code
before execution. Think of it as giving an English document to a translator and
they hand you the Arabic version.
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Hierarchy of Programming Paradigms
https://github.com/chrislgarry/Apollo-11/
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POP vs OOP
Procedural Oriented
Programming
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Object Oriented
Programming
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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Very brief history of C++
Quote: “C++ was designed to provide Simula’s facilities for program organization
together with C’s efficiency and flexibility for systems programming. It was
intended to deliver that to real projects within half a year of the idea. It succeeded.”
For details more check out A History of C++: 1979−1991
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Features of C++
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A Simple C++ Program
Let us begin with a simple C++ program that displays the
message “Welcome to C++!” on the console.
#include <iostream>
using namespace std;
int main()
{
// Display Welcome to C++ to the console
cout << "Welcome to C++!" << endl;
return 0;
}
Note: Clicking the green button displays the source code with interactive
animation and live run. Internet connection is needed for this button.
Welcome
Run
Note: Clicking the blue button runs the code from Windows. To enable the
buttons, you must download the entire slide file slide.zip and unzip the files
into a directory (e.g., c:\slide). If you are using Office 2010 or higher, check
PowerPoint2010.doc located in the same folder with this ppt file.
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Special Characters in C++
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Comments in C++
// This is a comment
cout << "Hello World!";
cout << "Hello World!"; // This is a comment
/* The code below will print the words Hello World!
to the screen, and it is amazing */
cout << "Hello World!";
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Extending the Simple C++ Program
Once you understand the program, it is easy to extend it to
display more messages. For example, you can rewrite the
program to display three messages.
#include <iostream>
using namespace std;
int main()
{
cout << "Programming is fun!" << endl;
cout << "Fundamentals First" << endl;
cout << "Problem Driven" << endl;
return 0;
}
Run
WelcomeWithThreeMessages
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Computing with Numbers
Further, you can perform mathematical computations and
displays the result to the console. Listing 1.3 gives such an
example.
#include <iostream>
using namespace std;
int main()
{
cout << "(10.5 + 2 * 3) / (45 - 3.5) = ";
cout << (10.5 + 2 * 3) / (45 - 3.5) << endl;
return 0;
}
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ComputeExpression
Run
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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The C++ Toolchain
• From the moment you write your C++ program to the moment it
executes; your program passes through many steps.
• At each step, a certain tool does something towards the process
of converting your program from a high-level language to an
executable program.
• This sequence of tools is called a toolchain.
• Most of the time, the toolchain comes with your IDE (e.g.,
Microsoft Visual Studio), or needs to be downloaded separately
and configured to work with your IDE.
• Expert Programmers can configure the fine details of the tool
chain (e.g., choose each tool, which version, other options).
• In any C++ IDE, pressing the build button starts the toolchain.
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The C++ Toolchain Main Programs
A program written in a high-level language is called a source program. It
has #include statements and may contain comments.
• The preprocessor strips out user comments and does replacements for
the include statements.
• A program called a compiler is used to translate the preprocessed
source program into the assembly code of the target machine.
• A program called the assembler then translates the assembly code to a
machine language program called an object program.
• The object program is often then linked using a linker with other
supporting library code before the object can be executed on the
machine.
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The Compilation Process
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Detailed Tool Chain Steps (1)
Assembly Code
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Detailed Toolchain Steps (2)
Assembly Code
Assembler
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C++ IDE Tutorial
You can develop a C++ program from a command window or from an
IDE. An IDE is software that provides an integrated development
environment (IDE) for rapidly developing C++ programs. Editing,
compiling, building, debugging, and online help are integrated in one
graphical user interface. Just enter source code or open an existing
file in a window, then click a button, menu item, or function key to
compile and run the program.
Examples of popular IDEs are Microsoft Visual Studio, Dev-C++,
Eclipse, CodeBlocks, CLion, and NetBeans. All these IDEs can be
downloaded for free or with a free student license.
IDEs might use different toolchains. For example, Microsoft Visual
Studio has their own compiler. CodeBlocks/CLion/Our server use
GCC. GCC/G++ is one of the world’s most famous compilers.
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Flowchart symbols
Terminal
Input/output
Process
Flowlines
Decision
Connector
Predefined process
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Algorithms in pseudo-code
You also can use English-like
phases to describe an algorithm.
In this case, the description is
called pseudocode.
Start
Input Name,
Hours, Rate
Calculate
Pay  Hours  Rate
Example:
• Input the three values into the
variables Name, Hours, Rate
• Calculate Pay = Hours * Rate
• Display Name and Pay
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Dislay
Name, Pay
End
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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Programming Style and Documentation
• Appropriate Comments
• Proper Indentation and Spacing Lines
• Block Styles
#include <iostream>
using namespace std;
int main()
{
cout << "(10.5 + 2 * 3) / (45 - 3.5) = ";
cout << (10.5 + 2 * 3) / (45 - 3.5) << endl;
return 0;
}
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Programming Fundamentals
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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Programming Errors
1. Syntax Errors
2. Runtime Errors
3. Logic Errors
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Syntax Errors
ShowSyntaxErrors
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Runtime Errors
ShowRuntimeErrors
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Run
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Logic Errors
ShowLogicErrors
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Run
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Common Errors
1.
2.
3.
4.
Missing Braces
Missing Semicolons
Missing Quotation Marks
Misspelling Names
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Programming Fundamentals
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Outline
•
•
•
•
•
•
Introduction and Computers (§§1.1–1.2)
Programming languages (§§1.3)
A simple C++ program for console output (§1.6)
C++ program-development cycle (§1.7)
Programming style and documentation (§1.8)
Programming errors (§1.9)
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