#include <stdio.h>
#include <stdlib.h>
int isprime(int n)
{
if (n <= 1)
return 0;
for (int i = 2; i <= n / 2; i++)
if (n % i == 0)
return 0;
return 1;
}
int main(int argc, char *argv[])
{
int n = 7;
printf("%d is %s prime\n", n, isprime(n) ? "a" : "not a");
return 0;
}