while loop

definition
syntax
flowchart
example
difference between for loop and while loop

More examples on while loop

Syntax of while loop

while (test expression) {
     statement/s to be executed.
}

flowchart

The while loop checks whether the  test expression is true or not. If it is true, code/s inside the body of while loop is executed,that is, code/s inside the braces { } are executed. Then again the test expression is checked whether test expression is true or not. This process continues until the test expression becomes false.

Example of while loop

Write a C program to find the factorial of a number, where the number is entered by user. (Hints: factorial of n = 1*2*3*...*n

/*C program to demonstrate the working of while loop*/

#include <stdio.h>

     int main(){

     int number,factorial;

     printf("Enter a number.\n");

     scanf("%d",&number);

     factorial=1;

     while (number>0){      /* while loop continues util test condition number>0 is true */

           factorial=factorial*number;

           --number;

}

printf("Factorial=%d",factorial);

return 0;

}

Output

Enter a number.

5

Factorial=120

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looping statements