#include <iostream>
using namespace std;

bool isPrime(int n)
/*
   Tests 2,3,4,.. n/2 if they are divisors of n.

*/
{
   int divisor=2;
   while (divisor <= n/2)
     {
        if (n%divisor==0) return false;        // divisor divides n   
        divisor++;
     }
     
  return true;
}

int main()
{
   int number;
   
   cout << "Please enter a number: ";
   cin >> number;
   
   if (isPrime(number)) cout << endl << number << " is a prime";
                   else cout << endl << number << " is not a prime";
 
   
   return 0;
}