By Fiaz Younas

Programming Presentation

A program written in a high-level language is called source code.

Source code is also called Source program.Source code of high-level language is save

with a specific extension.For example the program written in c++ save

with .ccp extension.

Source Code

#include<iostream> //preprocessor directivesUsing namespace std; //std stand for symbols

int main() //main function{

Cout<<“MY First c++ Program”;System(“pause”);

}

Example of source code is:

Compiler is a program that converts the instructions of a high level language into machine language as a whole.

High-level language[Source code]:Machine Language[ Object Code]:

Use the compiler to:Check the program that obey rules.Translate the program into machine

language.

Compiler

Source code Compiler Object code

Compiler can translate the programs of only those language for which it is written.

For example c++ compiler can translate only those program that are written in c++ language.

Note:

The process of linking the library files with object program is known as linking. These files accomplish different task such as input output.

A program that combines the object program with additional library files is known as linker.

This additional library files is used to create the executable file whose extension is .exe .

Linker

After compiling and linking the program file the new file is created that is known as executable file.

The process of running an executable file is known as executing.

The program must be loaded into main memory for execution.

A program that load the executable file into main memory is known as loader.

Executable File

Flow chart

A collection of rules for writing program in a programming language is known as syntax.

Basic structure of c++ program:#include<iostream>

using namespace std;int main()

{Cout<<“Program body”;System(“pause”);

}

C++ Syntax

Define a set of values and a set of operation on those values.

Category of c++ data types:1. Simple data type2. Structure data type3. Pointer data type Simple data type: A data type is called simple if variable of that type

can store only one value at a time. e.g. int a float b; Simple data type is building block of structure data

type.

Data types:

Integral: integers (numbers without a

decimal) e.g. 12,34 etcFloating-point:

decimal numbers e.g.12.34 ,45.5Enumeration type:

user-defined data typeSyntax of declare a variable and data

type:Datatype variable_name;

Category of simple data type

int data type:Integers in C++, as in mathematics, are

numbers such as the following:-6728, -67, 0, 78, 36782, +763Note the following two rules from these examples:1. Positive integers do not need a + sign in front

of them.2. No commas are used within an integer. Recall

that in C++, commas are used to separate items in a list. So 36,782 would be interpreted as two integers: 36 and 782

Three most commonly used data type in integer

Bool DATA TYPE:The data type bool has only two values : true

and false.The central purpose of this data type is to

manipulate logical (Boolean) expressions.Char DATA TYPE:The data type char is the smallest integral data

type. It is mainly used to represent characters—that

is, letters, digits, and special symbols.e.g. 'A','a','0','*','+','$','&',''

Contin.

To deal with decimal numbers, C++ provides the floating-point data type.

It is also called real type data. It include positive and negative values.

Types of Floating Point:1. Float2. Double 3. Long double

Floating-Point Data Types

Data type Size in Bytes Description

Float 4 3.4 x10^-38 to 3.4 x10^+38

Double 8 1.7x10^-308 to1.7x10^+308

Long double 10 1.7x10^-4932 to1.7x10^+4932

Contin.

Structure data typeEach data item is a collection of other data

items.E.g. array , structure , classes.Pointer data type:The values belonging to pointer data types

are the memory addresses of your computer.pointer variables store memory addresses.Syntax for pointer declaration:dataType*variable;

Contin.

Operator are the symbols that are used to perform certain operations on data.

C++ provides a variety of operators.1. Arithmetic Operators2. Relations Operations3. Logical Operations4. Assignments Operators5. Increment and decrement Operators6. Compound Assignment Operators

Operators

Arithmetic operator is a symbol that performs mathematical operation on data.

C++ provides many arithmetic operators.

Arithmetic Operator

Operators Symbol Descriptions

Addition + Adds two values

Subtraction - Subtracts one from another value

Multiplication * Multiplies two values

Division / Divides one by another value

Modulus % Give the remainder of division of tow integers

Example if A=10 and B=5 then arithmetic operator and results

Contin. operators

Operation Result

A+B 15

A-B 5

A*B 50

A/b 2

A%B 0

The relational operators are used to specify conditions in program.

A relational operators compare two values.Also called comparison operators.C++ provides the following six relational

operators with their description: Greater than[>]:Greater than operator returns true if the value

on left side of > greater than the value on the right side. Otherwise returns false.

Relation Operators

Less than [<]:Less than operator returns true if the value on left side of < less than the value on the right side. Otherwise returns false.

Equal to ==:Equal to operator returns true if the value on both side of = equal. Otherwise returns false.

Greater than or equal to [>=]:Greater than or equal to operator returns true if the value on left side of >= greater than or equal to the value on the right side. Otherwise returns false.

Contin.

Less than or equal to [<=]:Less than or equal to operator returns true if the value on left side of <= less than or equal to the value on the right side. Otherwise returns false.

Not Equal to !=:Not Equal to operator returns true if the value on left side of != is not equal to the value on the right . Otherwise returns false.

Contin.

Example if A=10 and B =5 the relational operator and their result

Contin>

Relational Expression

Result

A>B True

A<B False

A<=B False

A>=B False

A==B False

A!=B True

The Logical operators are used to evaluate compound condition.

Logical operators are as follows:1. AND Operators(&&)2. OR Operators(||)3. NOT Operators(!)1) AND Operators(&&)The symbols used for AND operator is (&&). It is used to evaluate two condition. It produce result true if both condition is true. It produce result false if any of the condition is false.

Logic operators

Contin. Table of AND operatorCondition 1 Operator Condition 2 Result

False && False False

False && True False

True && False False

True && True True

Example:Suppose we have tow variables A=100 and

B=50. the compound condition (A>10) &&(B>10) is true .it contain two conditions and both are true. So whole compound condition is true.

The compound condition (A>50) &&(B>50) is false. it contain two conditions one is true and one is false. So whole compound condition is false.

Contin.

2) OR Operators(||)The symbols used for OR operator is (||). It is used to evaluate two condition. It produce result true if any of the condition is true. It produce result false if both condition are false

Contin.

Condition 1 Operator Condition 2 Result

False || False False

False || True True

True || False True

True || True True

Example:Suppose we have tow variables A=100 and

B=50. the compound condition (A>50) ||(B>50) is true .it

contain two conditions and one condition is true. So whole compound condition is true.

The compound condition (A>500) ||(B>500) is false. it contain two conditions and both are false. So whole compound condition is false.

Contin.

3) NOT Operators(!) The symbol used for NOT is (!). It is used to reverse the result of a condition It produces true if the condition is false. It produces false if the condition is true.Example:Suppose we have tow variables A=100 and B=50.

the condition !(A==B) is true .The result of (A==B) is false but NOT operator converts it into true.

The condition !(A>B) is false .The result of (A>B) is true but NOT operator converts it into false.

Contin.

The assignment operator = is used in assignment statement to assign a value or computational result to a variable.

Syntax:Variable_name= expression;Variable_name it is the name of variable= it the assignment

operatorExpression it is any valid expression; statement terminator

Assignments Operators

The increment operator is used to increase the value of variable by one.

It is denoted by the symbol ++.The increment operator cannot increment the

value of constants and expressions.For example:Valid statements Invalid statementsA++,x++ 10++

(a+b)++,or ++(a+b)

Increment Operator

Forms of increment operator: PrefixIn prefix form ,the increment operator is

written before the variable as follows:++y; PostfixIn postfix form ,the increment operator is

written after the variable as follows:y++;

Contin.

Let A=++B and A=B++ are different:In prefix: A=++BIt increment the value of B by one.It assign the value of B to A.++B;A=B;In postfix: A=B++It assign the value of B to A.It increment the value of B by one.A=B;++B;

Difference between prefix and postfix by example

The decrement operator is used to decrease the value of variable by one.

It is denoted by the symbol --.The decrement operator cannot decrement

the value of constants and expressions.For example:Valid statements Invalid statementsA--,x-- 10--

(a+b)--,or --(a+b)

Decrement Operator

Forms of decrement operator: PrefixIn prefix form ,the decrement operator is

written before the variable as follows:--y; PostfixIn postfix form ,the decrement operator is

written after the variable as follows:y--;

Contin.

Let A=--B and A=B--are different:In prefix: A=--BIt decrement the value of B by one.It assign the value of B to A.--B;A=B;In postfix: A=B--It assign the value of B to A.It increment the value of B by one.A=B;--B;

Difference between prefix and postfix by example

That combine assignment operator with arithmetic operators.

We are used to perform mathematical operator more easily.

Syntax:Variable op=expressionE.g. N+=10; is equalvent to N=N+10;

Compound Assignment Operators

The syntax of cout and << is:

Called an output statementThe stream insertion operator is <<Expression evaluated and its value is printed

at the current cursor position on the screen

“Cout "and "cin"

cin is used with >> to gather input

The stream extraction operator is >>For example,

cin >>a;Causes computer to get a value of type intPlaces it in the variable a

Contin.

If statementIf else statementIf- else –if statementNested if statementSwitch case statement

Decision statements

If is a decision-making statement.It is the simplest form of decision statement.Syntax:If(condition){Statement1;Statement2;..StatementN;}

If statement

Condition is given as relational expression.If the condition is true the statement or set of

statement is executed.If the condition is false the statement or set of

statement is not executed.

Contin.

#include<iostream>using namespace std;int main(){

int a;cin>>a;if(a>40)

cout<<"you are pass";system("pause");

}

Example

It execute one block of statement when the condition it true and the other if the condition is false.

In any situation, one block is executed and the other Is skipped.Syntax:If(condition){Statement(s);}else{Statement(s);}

If else statement

#include<iostream>using namespace std;int main(){

int a;cin>>a;if(a>40)

cout<<"you are pass";else

cout<<"you are fail";system("pause");

}

Example

Use to choose one block of statements from many block of statements.

It is used when there are many option and only one block of statement should be executed on the basis of a condition.

If- else –if statement

Syntax:If(condition){Block 1;}else if(condition){Block2;}Else{Block N;}

Contin.

#include<iostream>

using namespace std;

int main()

{

int a;

cout<<"enter a number";

cin>>a;

if(a>0)

cout<<"the number is positive";

else if(a<0)

cout<<"the number is negative";

else

cout<<"the number is zero";

system("pause");

}

Example

An if statement within an if statement is called nested if statement.

In structure, the enter into the inner if only when the outer condition is true.

If the condition is false the control moves to the outer part of the outer if and skipped the inner if statement.

Neasted if statement

syntax

Example

It is an alternative of nested if statement. It can be used easily when there are many choices available and only one should be

executed.

Syntax:

Switch(expression)

{

case val 1:

Statements1;

break;

.

.

case val n:

Statements1;

break;

Default:

Statements1;

}

Switch case statement

Example

LOOP:For LoopWhile LoopDo while Loop

Control Statement

For loop execute one or more statement for a specified number of times.

Syntax:For( intialization ; condition ;

increment/decrement ){Statement(s);}

For Loop

#include<iostream>using namespace std;int main(){ int n; for(n=1;n<=5;n++) cout<<n<<endl; system("pause");}

Example

While loop executes one or more statement while the given condition remain true.

It is useful where the number of iterations is not know in advance.

Condition become before the body of loop.Syntax:While(condition){Statement(s);}

While Loop

#include<iostream>using namespace std;int main(){

int n=1;while(n<=5){

cout<<"Pakistan"<<endl;n++;

}system("pause");

}

Example

Do while loop executes one or more statement while the given condition remain true.

Important where a statement must be executed at least once.

Condition become after the body of loop.SyntaxDo{Statement(s)}While(condition);

Do while Loop

#include<iostream>using namespace std;int main(){

int c=1;do{

cout<<c<<endl;c++;

}while(c<=10);system("pause");

}

Example