Thread: Reverse of an integer

The problem:

Code:

The name of the function's name should be reverse. Let the 
name of its value parameter be x (which is an int).  The 
return datatype should be int.  Use the main() driver program 
provided below to test your function:

#include <iostream>
using namespace std;

// insert the reverse function here.

int main()
{
  int num;
  cin >> num;
  cout << "Reverse of " << num << " is " << reverse(num) << endl;
  return 0;
}

I know what I should do to obtain the reverse number, but its harder when using a function int. The program should handle any as much digits it can handle. So I know I should use a loop, and also you should know the number of digits - I've done that. My question is what is the proper way of returning the reverse digits. And by the way our lesson is about REFERENCES AND REFERENCE PARAMETER.