The document provides an introduction to computer programming and the C++ programming language. It discusses what a computer program is, different types of programs, and the process of computer programming. It then covers key concepts in C++ programming including data types, variables, constants, input/output, and basic program structure. The document is intended to teach programming fundamentals and provide an overview of C++ for beginners.

1. 1
INTRODUCTION
COMPUTER
PROGRAMMING
Computer Program
 A computer program is a sequential set/collection of
instructions that performs a specific task when executed by
a computer.
 Everything a computer does is done by using a computer
program
 A computer program is usually written by a computer
programmer in a programming language.
 Some examples of computer programs:
 Operating system.
 A web browser like Mozilla Firefox and Apple Safari can be used
to view web pages on the Internet.
 An office suite can be used to write documents or spreadsheets.
 Video games are computer programs.

2. 2
Computer Programming
 The process of developing and implementing various sets of
instructions to enable a computer to do a certain task.
 These instructions are considered computer programs and help
the computer to operate smoothly.
 People who program are referred to as programmers and write
their code in a programming language.
Pseudocode, Algorithm
and Flow charts

3. 3
PSEUDOCODE, ALGORITHMS
AND FLOWCHARTS
 Computer programming can be divided into two
phases:
 Problem solving phase
 Make an ordered sequence of steps that solves a
problem
 These sequence of steps is called an algorithm
 Implementation phase
 implement using a programming language
Introduction to C++
 C is a programming language developed in the
1970's alongside the UNIX operating system.
 C++ is an “extension” of the C language.
 C++, as opposed to C, supports “object-oriented
programming.”
 C++ is pronounced as C plus plus, is a powerful
computer programming language.
 C is a procedural programming language.
 C++ is a an object oriented programming
language.

4. 4
Writing C++ programs
 The source code of a c++ program is stored on the disk
with file extension .cpp ( stands for c plus plus).
 Program stored on a text file on disk
 Different text editors are used for code writing
 The boreland c++ and turbo++ have their own editors for
code writing.
 Visual studio IDE(integrated development environment)
Steps in compiling C++ Program
 C++ compiler translates the source program with .cpp
extension into machine code called object code and
stored in newfile with .obj extension.
 Object code is then linked to libraries
 After linking an executable file with extension .exe is
created.
 The executable program is then executed.

5. 5
Stages of compiling a C program
Preprocessing
 First stage of compilation is called preprocessing.
 The C preprocessor modifies a source file before handing it over to the
compiler, like defining constants # define and including header files i.e.
# include<>.
 The preprocessors are the directives, which give instructions to the
compiler to preprocess the information before actual compilation start.
 All preprocessor directives begin with #
Making the Object file: The compiler
 After the C Preprocessor has included all the header files, the compiler
then COMPILES the program.
 Compiler changes the C source file with .cpp extension into an Object
code file with .o extension.
 The object file contains the binary version of the source code.

6. 6
Putting it all together: The linker
 The job of the linker is link together a bunch of object files(.o files) into a
binary executable.
 The file created after linking is ready to be loaded into memory and
executed by the system.
Preprocess, Compile, Link, execute

7. 7
Structure of c++ program.
 In every programming language there are some
fundamentals you need to know before you can write the
most basic programs.
 C++ program mainly consist of 3 parts
1. Preprocessor directives
2. The main() function
3. C++ statements
Header file
 It is a source file that contain definitions of library
functions/objects.
 Library functions:
 Those functions which are predefined in c++ language i.e. built in
functions.
 Added into program at the compilation of program.
 Only added if function defined in it is used in program.

8. 8
The main function
 The main() function indicates the beginning of the program.
 The parenthesis following function name is distinguishing feature of
function and must be included
 The syntax
 void main()
 {
 Program statements…
 }
C++ statements
 The statements of the program are written under the main()
function between curly braces
 {
 …………………statements………………….
 }
 Every function must use this pair of braces around its body.
 Statements are the body of program
 Each statement in C++ ends with a semicolon ;.
 C++ is a case sensitive language.

9. 9
Program statements & namespace
 Statements of program are written under the main function inside curly
brackets.
 int main()
 {
 cout<<“ statement”;
 return 0;
 }
 The first statement tells the compiler to display the quoted phrase.
 Second statement returns a 0 value to who ever calls it.
 The built in C++ library routines are kept in the standard namespace.
 The standard C++ library is defined in this standard namespace.
Output using Cout
 cout<<“ this is my first c++ program”;
 It causes the phrase in quotation marks to be displayed on
the screen.
 It shows the standard output stream.
 The ‘<<‘ operator is called insertion or put to operator.
 Directs the string constant “this is c++ program” to the cout.
 cout sends it to display screen.
 The statement in “ this is my c++ program” is a string
constant example.

10. 10
Keywords
The words that are used by the language and carries
special meanings are called keywords.
 Keywords are predefined reserved words used in programming.
Keywords are part of the syntax and they cannot be used as an
identifier.
 For example: int salary; Here, int is a keyword that indicates
‘salary' is a variable of type integer.
 Keywords appear in blue in Visual C++.
 Do not use keywords as variable and constant names!!
For e.g.
 The word main is used to indicate the starting of program.
 include is used to add header files.
 int to declare an integer type variable.
C Keywords
 As C is a case sensitive language:
 all keywords must be written in lowercase. Here is a list of all
keywords allowed in ANSI C.

11. 11
Tokens
 A program statement consists of variable names, keywords,
constants, punctuation marks, operators etc.
 In C++ these elements are called tokens.
 In the following program segment tokens are
 main()
 {
 int, b;
 }
 Tokens are main, {,}, int, a, b , (,) are tokens
Identifiers
 An identifier is a name that is assigned by the user for a program
element such as variable, functions and structures.
 Identifier must be unique:
 They are created to give unique name to a entity to identify it
during the execution of the program. For example:
 int length;
 char nmfirst=‘a’;
Note:
 Identifier must be different from keywords. Better to have a
meaningful name for the identifier.

12. 12
variables
 Variables are fundamental part of any programming language.
 A variable is a container (storage area) to hold data.
continued
 To indicate the storage area, each variable should be given a unique
name (identifier).
 variable names are just the symbolic representation of a memory
location. For example:
 Float gpa=3.5; // gpa is a variable of type float and the value assigned is
3.5.
 The value of the variable can be changed, as the name suggests
“variable”.

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Rules for naming a variable name
 A variable must be declared before using.
 A variable name can have letters (both uppercase and lowercase letters),
digits and underscore only.
 The first letter of a variable should be either a letter or an underscore.
 Blank spaces are not allowed in a variable name.
 Special characters can not be used in variable name.
 The maximum length of variable name depends on compiler of c++.
 variable name pay and Pay will be considered different.
Constants or literals
 Constant is a fixed value that does not change during program
execution.
 Constant must have to be initialized at the time of creating it and new
values cannot be assigned later to it.

14. 14
Constant definition in C++
Constant definition by using const keyword

15. 15
Constant definition by using #define
preprocessor
Data types in c++
C++ has five data types
 int integer
 Float floating point
 Double double precision
 Char characters
 Bol Boolean.

16. 16
Integer variables
 variable that holds the integer data, is known as integer variable.
 a number without fractions or decimal point.
 E.g. 11, 222, 345 etc.
 takes two or four bytes in memory.
Size of integers
 A short int is two bytes on most computers.
 A long int is usually four bytes.
 int can be two or four bytes long for modern compilers.
 Determines the Size of Variable Types on Your Computer.

17. 17
Float data type
 Float represent real or floating point data.
 Float data type can be signed or unsigned.
 E.g. 11.09, 34.81, -5.88 .
 Storage capacity: 4 bytes
Bool data type
 The word bool stands for Boolean.
 Used to declare logical type variables.
 Only two values can be stored
 True or false
 True=1
 False=0

18. 18
General form of a C++ program
// Program description
#include directives
int main()
{
constant declarations
variable declarations
executable statements
return 0;
}
Example 0 – adding 2 numbers
 Peter: Hey Frank, I just learned how to add two numbers
together.
 Frank: Cool!
 Peter : Give me the first number.
 Frank: 2.
 Peter : Ok, and give me the second number.
 Frank: 5.
 Peter : Ok, here's the answer: 2 + 5 = 7.
 Frank: Wow! You are amazing!
 after Frank says “2”, Peter has to keep this number in his mind.
2 5 7First number: Second number: Sum:
 after Frank says “5”, Peter also needs to keep this number in his mind.

19. 19
The Corresponding C++ Program
#include <iostream>
using namespace std;
int main()
{
int first, second, sum;
cout << "Peter: Hey Frank, I just learned how to add”
<< “ two numbers together."<< endl;
cout << "Frank: Cool!" <<endl;
cout << "Peter: Give me the first number."<< endl;
cout << "Frank: ";
cin >> first;
cout << "Peter: Give me the second number."<< endl;
cout << "Frank: ";
cin >> second;
sum = first + second;
cout << "Peter: OK, here is the answer:";
cout << sum << endl;
cout << "Frank: Wow! You are amazing!" << endl;
return 0;
}
#include <iostream>
using namespace std;
int main()
{
int number_of_pods, peas_per_pod, total_peas;
cout << "Press return after entering a number.n";
cout << "Enter the number of pods:n";
cin >> number_of_pods;
cout << "Enter the number of peas in a pod:n";
cin >> peas_per_pod;
total_peas = number_of_pods * peas_per_pod;
Demo Example 1

20. 20
cout << "If you have ";
cout << number_of_pods;
cout << " pea potsn";
cout << "and ";
cout << peas_per_pod;
cout << " pea in each pod, then n";
cout << "you have ";
cout << total_peas;
cout << " peas in all the pods.n";
return 0;
}
Demo Example 1
C++ comments
 Comments appear in green in Visual C++.
 Comments are explanatory notes; they are ignored by the
compiler.
 There are two ways to include comments in a program:
// A double slash marks the start of a
//single line comment.
/* A slash followed by an asterisk marks
the start of a multiple line comment. It
ends with an asterisk followed by a
slash. */

21. 21
Programming Style
C++ is a free-format language, which means
that:
 Extra blanks (spaces) or tabs before or after
identifiers/operators are ignored.
 Blank lines are ignored by the compiler just like
comments.
 Code can be indented in any way.
 There can be more than one statement on a
single line.
 A single statement can continue over several
lines.
In order to improve the readability of your program, use
the following conventions:
 Start the program with a header that tells what the
program does.
 Use meaningful variable names.
 Document each variable declaration with a comment
telling what the variable is used for.
 Place each executable statement on a single line.
 A segment of code is a sequence of executable
statements that belong together.
 Use blank lines to separate different segments of code.
 Document each segment of code with a comment
telling what the segment does.
Programming Style (cont. )

22. 22
What makes a bad program?
 Writing Code without detailed analysis and
design
 Repeating trial and error without understanding
the problem
 Debugging the program line by line, statement
by statement
 Writing tricky programs
Continued…
 Symbol used for grouping and separating code are known as punctuators
 “()” , “{}” “[ ]” : = # comma, semicolon, colon.
 The following characters are used as punctuators in C++.
 Brackets [ ] opening and closing brackets indicate single and multidimensional
array subscript.
 Parentheses ( ) opening and closing brackets indicate functions calls, function
parameters for grouping expressions etc.
 Braces { } opening and closing braces indicate the start and end of a compound
statement.
 Comma , it is used as a separator in a function argument list.
 Semicolon ; it is used as a statement terminator.
 Colon : it indicates a labeled statement or conditional operator symbol.
 Asterisk * it is used in pointer declaration or as multiplication operator.
 Equal sign = it is used as an assignment operator.
 Pound sign # it is used as pre-processor directive.

23. 23
Maniupulators
 These are operators that are used with insertion operator (<<) to control
format of data.
 The endl manipulator stands for end of line. It is predefined iostream
manipulator.
 #include<iostream>
 int main()
 {
 cout<<“ I am “<<endl<<“pakistani”;
 return 0;
 }
 Output:
 I am // end of line
 Pakistani.
manipulators
 ‘setw’ stands for setwidth. This manipulator is used to set the width of
output on the output device.
 Setw() manipulator is a part of “iomanip.h” header file.
Syntax
 Setw(n)
Where n specifies the width of output field. It is an integer value.
 For e.g. to print “pakistan” in first 10 columns and “islamabad” in next 15
columns, the output statement written as
 Cout<<setw(10)<<“pakistan”<<setw(15)<<“islamabad”;
 Output would be

24. 24
Setw continued…
Initialization of variables
 Assigning known value to a variable at the time of declaration is called
initializing of variable.
 When variable is declared, Memory location is assigned.
 Value in memory location is also assigned to that variable.
 In order to assign variables of type int and assigning known values it
can be written as :
 int a=30;
 int b=40;
 int c ;
 c= a+ b;
 Cout<<c ;

25. 25
Continued…
 A program that assign values to different variables at the time of
declaration and print the assigned values on computer screen.
 #include<iostream>
 using namespace std;
int main()
 {
 int xyz=4, b=2000;
 double xy=6.9;
 cout<<name<<xyz<<xy<<b;
 getch();
 }
constants
 A quantity that can not change its value during the execution of
program is called constant.
Four type of constants
 Integer constants
 Floating point constants
 Character constants
 String constants

26. 26
Constant continued..
 A numerical value without a decimal part is called integer constant.
Floating point constant:
 Numeric values that has an integer as well as a decimal part is called
floating point constant
Character constants:
 A single character enclosed in a single quotation mark is called character
constant. For e.g. ‘a’, ‘/’, and ‘+’ represents character constants.
String constants:
 A sequence of characters consisting of alphabets, digits and special
characters enclosed in double quotation marks is called string constants.
for e.g. “ I study in bahria university” in “ semester -1”
Operators and types
 Operators are special symbols that tells the compiler to perform specific
mathematical or logical functions
C++ divides the operators into following groups:
 Arithmetic operators
 Comparison/Relational operators
 Logical operators
 Assignment operators
 Bitwise operators

27. 27
Arithmetic operators
Relational/Comparison Operator
 Relational operator is an operator that tests or defines some kind
of relation between two entities

28. 28
Logical Operators
Logical operators:
 The logical operators are used to combine one or more relational
expression.