#include <iostream>

using namespace std;

class Silly {
   public:
      Silly(int & x): xRef(x){}

      void X(int val) {
          xRef = val;
      }

      int X(void) const {
         return xRef;
      }

   private:
       int & xRef;
      
};

int main() {
    int x = 5;
    int y = 2001;

    Silly aClass(x);

    int & xRef = x;

    cout << " x = " << x << endl;
    cout << " xRef = " << xRef << endl;
    cout << " aClass.X() = " << aClass.X() << endl;

    cout << endl;


    xRef = -99;
    cout << " x = " << x << endl;
    cout << " xRef = " << xRef << endl;
    cout << " aClass.X() = " << aClass.X() << endl;
    cout << endl;

    x = 1001;
    cout << " x = " << x << endl;
    cout << " xRef = " << xRef << endl;
    cout << " aClass.X() = " << aClass.X() << endl;
    cout << endl;

    aClass.X(43);
    cout << " x = " << x << endl;
    cout << " xRef = " << xRef << endl;
    cout << " aClass.X() = " << aClass.X() << endl;
    cout << endl;

    // notice, this copys the value, it does not change the reference.
    xRef = y;
    cout << " x = " << x << endl;
    cout << " xRef = " << xRef << endl;
    cout << " aClass.X() = " << aClass.X() << endl;
    cout << endl;

    return 0;
}