while loop :

-It is an entry controlled loop statement.

-The test condition is evaluated and if the condition is true,then the body of the loop is executed.

-The execution process is repeated until the test condition becomes false and the control is transferd out of the loop.

-On exit,the program continue with the statement immediately after the body of the loop.

-This process continue until the test condition becomes false and the control is transferred out of the loop.

Syantax : 

while( test expression )

{

       Body of the loop

}

statement -x;

Program :

#include<stdio.h>
#include<conio.h>

void main();

{

int no=1,sum=0;

while(no<=100)

{

sum=sum+no;

no=no+1;

}

printf("\n sum of no's between 1 and 100:%d",sum);

getch();

}

Output :

sum of no's between 1 and 100 is:5050