while loop in C

While loop is also known as a pre-tested loop. In general, a while loop allows a part of the code to be executed multiple times depending upon a given boolean condition. It can be viewed as a repeating if statement. The while loop is mostly used in the case where the number of iterations is not known in advance.

Syntax of while loop in C language

The syntax of while loop in c language is given below:

  1. while(condition){  
  2. //code to be executed  
  3. }  

Flowchart of while loop in C

flowchart of c while loop

Example of the while loop in C language

Let's see the simple program of while loop that prints table of 1.

  1. #include<stdio.h>  
  2. int main(){    
  3. int i=1;      
  4. while(i<=10){      
  5. printf("%d \n",i);      
  6. i++;      
  7. }  
  8. return 0;  
  9. }    

Output

1
2
3
4
5
6
7
8
9
10

Program to print table for the given number using while loop in C

  1. #include<stdio.h>  
  2. int main(){    
  3. int i=1,number=0,b=9;    
  4. printf("Enter a number: ");    
  5. scanf("%d",&number);    
  6. while(i<=10){    
  7. printf("%d \n",(number*i));    
  8. i++;    
  9. }    
  10. return 0;  
  11. }   

Output

Enter a number: 50
50
100
150
200
250
300
350
400
450
500

Enter a number: 100
100
200
300
400
500
600
700
800
900
1000