/* Pass-by-reference can lead to aliasing
  * aliasing is when you can use two names to refer to the same location
  * in memory.
  * The output in this example is predictable, so, in that sense, it isn't a problem.
  * But it does mean you need to be careful when you call functions with 
  * pass-by-reference. You need to know exactly what you are doing.
  */

#include <iostream>
using namespace std;

int global = 1;

int open_to_problems (int &a, int &b) {
	a = a + global;
	b = b + global;
	
	return 0;
}

int main () {
  int x = 10, y = 20;
	
  cout << "Before open_to_problems, x = " << x << ", y = " << y << endl;
  open_to_problems( x, y );
  cout << "After open_to_problems, x = " << x << ", y = " << y << endl;

  cout << "Before open_to_problems, x = " << x << endl;
  open_to_problems( x, x );
  cout << "After open_to_problems, x = " << x << endl;
  
  cout << "Before open_to_problems, x = " << x << endl;
  open_to_problems( global, x );
  cout << "After open_to_problems, x = " << x << endl;
    
  return 0;
}