16 - WAP to check whether the entered number is prime or not.

WAP to check whether the entered number is prime or not.

A positive integer which is only divisible by 1 and iself is known as prime number. For example: 13 is a prime number because it is only divisible by 1 and 13 but, 15 is not prime number because it is divisible by 1, 3, 5 and 15.

#include <stdio.h>
int main()
{
  int n, i, flag=0;
  printf("Enter a positive integer: ");
  scanf("%d",&n);
  for(i=2;i<=n/2;++i)
  {
      if(n%i==0)
      {
          flag=1;
          break;
      }
  }
  if (flag==0)
      printf("%d is a prime number.",n);
  else
      printf("%d is not a prime number.",n);
  return 0;
}

Output 

Enter a positive integer: 29
29 is a prime number.