While Loop in C Programming Language

While Loop :

While Loop is Entry Controlled Loop

Syntax of While Loop :

while(test condition) 
{
body of loop  
}

Steps of Execution :

1. Test Condition is Evaluated First and if 'Test Condition' is True then 'body of Loop' is Executed.
2. After Execution , Once Again 'Test Condition' is Evaluated if it is True then 'body of loop' Executed once again
3. If Result of test condition is False Then it Continues with the statement immediately after the body of loop.

Body of Loop May have one/more Statements

1. Curly Braces are used to Separate Block
2. If While Loop Contain Single Statement as part of body then Pair of Braces are required
3. Opening & Closing Braces are needed only if the body contain two / more Statements

Example of Multiple Statement as a Part of While Body

#include<stdio.h>
#include<conio.h> 
void main()
{
int i =0;
while(i<10 )
   {
   printf("Statement 1");
   printf("Statement 1");
   i++ ;
   }
getch() 
}

What is Entry Controlled Loop ?

1. Entry is Given into the 'Loop Body' Only when the 'Entry Condition' is True
2. In Short Condition is Tested before entering into Loop.

Illustration :

#include<stdio.h>
#include<conio.h> 
void main()
{
int n =0;
while(n<10 )
   {
   printf (" John ");
   n++ ;
   }
getch() 
}

Posted in: While Loop