Write a c program to check is a number prime or not

program to check is a number prime or not

#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)
{
// condition for non-prime
if (n % i == 0)
{
flag = 1;
break;
}
}
if (n == 1)
}
printf("1 is neither prime nor composite.");
}
else
{
if (flag == 0)
printf("%d is a prime number.", n);
else
printf("%d is not a prime number.", n);
}
return 0;
}