Program to Check Whether a Number is Prime or Not

PROGRAM :  Number is Prime or Not 

#include<stdio.h>

#include<math.h>

int isPrime(int n)

{

     int root,i;

//Calculating squae root of n

      root=sqrt(n);

/*  check n against all numbers from 2 to square root of n,

               whether n is divisible by the number */

      for(i=2;i<=root;i++)

      {

//if divisible, not prime (return zero)

                 if(n%i==0)

                   return 0;

      }

                  return 1;

}

int main()

{

    int input;

    printf("\nEnter the number\n");

               scanf("%d",&input);

    if(isPrime(input))

              printf("\nIt is prime\n");

    else

            printf("\nIt is not prime\n");

return 0;

}

OUTPUT :