C Program to Check a number whether it is prime or not using while loop

1. 
   
3. //C Program to Check a number whether it is prime or not using while loop
4. 
   
5. #include <stdio.h>
6. int main() {
7.     int number, i=2, a = 0;
8.     printf("Enter a positive Number To Check whether it is prime or not:- ");
9.     scanf("%d", &number);
10. 
    
12.  if(number<0)
13.     {
14.         printf("You Entered Negative Number , Please Enter Positive Number.");
15.         exit(0);
16.      }
17. 
    
18.     while (i <= number / 2 ) 
19. {
20.         if (number % i == 0) {
21.             a = 1;
22.             break;
23.         }
24.           i++;
25.     }
26. 
    
27.     if (number == 1) {
28.         printf("1 is neither prime number nor composite number.");
29.     }
30.     else {
31.         if (a == 0)
32.             printf("%d is a prime number.", number);
33.         else
34.             printf("%d is not a prime number.", number);
35.     }
36. 
    
37.     return 0;
38. }

Output