#include <iostream.h>
#include <conio.h>
 
void PrimeTest(int);
 
main()
{
      int num;
      cout<<"Enter number: ";   
      cin>>num;
 
      PrimeTest(num);
 
getch();
}
 
 
void PrimeTest(int n)
{
   bool isPrime=true;
 
     for(short i=2;i<=(n-1);i++)
     {
       if (n%i==0)
       {
          isPrime=false;
          break;           
       }
       else
       {
         isPrime=true;    
       }
     }
 
   if ((isPrime) || (n<=2))
   {
      cout<<n<<" is a prime number!";            
   }
   else
   {
      cout<<n<<" is not a prime number!";  
   }      
}

#include <iostream>
using namespace std;
 
bool PrimeTest(int);
 
int main()  //prefer int main() instead of void main() or void main(void)
{
	int num;
	cout<<"Enter number: ";   
	cin>>num;
	if (PrimeTest(num))
		cout<<num<<" is a prime number!"; 
	else
		cout<<num<<" is not a prime number!"; 
	return 0;
}
 
bool PrimeTest(int n)
{
	bool result=true;
 
	for(short i=2;i<=(n-1);i++)
	{
		if (n%i==0)
		{
			result=false;
			break;           
		}
		else
		{
			result=true;    
		}
	}
	return result;    //added because must return sth now
}

for (int k=0;k<1000;++k)
{
   if (PrimeTest(num))
      cout<<num<<" is a prime number!";
   else
      cout<<num<<" is not a prime number!"; 
}

for (int k=0;k<1000;++k)
{
   PrimeTest(num);
}