A Program in which the user enters an integer, and the program indicates if that integer was a prime number or not

The question is:

"Create a program that asks the user to enter any integer, and then indicates to the user if the number entered was prime or not. Do this by creating a C++ function whose input is any integer; by counting the number of factors, your function should return true if the input is prime, and false otherwise."

Here's my code (please give direction not a precise answer):

using namespace std;

int i;

bool isPrime (int x)

    {
        if (x%i == 0)
        {
            return true;
        }
        else
        {
            return false;
        }
    }


int main()

{

    for (int i = 2; i < x; i++)

    {

    }
}

Thanks!