C Program to check whether the entered number is prime or not

/* C program to check whether the entered number is prime or not. */

#include"stdio.h"

void main()

{

int num, i, occur = 0;

printf("Enter a positive integer: ");

scanf("%d",&num);

for(i=2; i<=num/2; ++i)

{

if(num%i==0)

{

occur=1;

break;

}

}

if (occur==0)

printf("%d is a prime number.",num);

else

printf("%d is not a prime number.",num);

}

Output: