[C++] Prime Number Program

[ksrocks333]

Tells if number is prime or not.
Ask questions if you have them.

#include <iostream.h>
#include <math.h>

int main()
{
    int num, x=0;
    
    cout<<"Enter a number: ";
    cin>>num;
    while(num<2)//deals with incorrect user input
    {
         cout<<"No, a number larger than 1."<<endl;
         cout<<"Try again: ";
         cin>>num;
    }
	for (int i=2; i<=sqrt(num)&&x==0; i++)// basically saying divide your number by 2, then 3, so on.
	 {		         //sqrt because you only need to check first half of the numbers of the inputted number
		if (num % i == 0)//if at any time, the number divides perfectly, it's not prime
		{
            x=num; //this breaks the loop
			cout << "It is not prime number." << endl;
			cout<<num<<"/"<<i<<"= "<<num/i<<endl;
		}
	 }
	 if(x==0)//if the value we've set as x is still zero, nothing was divided perfectly, it's prime.
	 {
             cout<<"Yes, that's a prime number."<<endl;
     }

system ("PAUSE");
return 0;
}