#include <iostream>
using namespace std;
 
bool check_prime(int);
 
int main() {
 
  int n;
 
  cout << "Enter a positive  integer: ";
  cin >> n;
 
  if (check_prime(n))
    cout << n << " is a prime number.";
  else
    cout << n << " is not a prime number.";
 
  return 0;
}
 
bool check_prime(int n) {
  bool is_prime = true;
 
  // 0 and 1 are not prime numbers
  if (n == 0 || n == 1) {
    is_prime = false;
  }
 
  for (int i = 2; i <= n / 2; ++i) {
    if (n % i == 0) {
      is_prime = false;
      break;
    }
  }
 
  return is_prime;
}

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