#include <iostream>

using namespace std;

void swap(int &x, int &y)
{

}

int main()
{
 int x=5;
 int y=10;
 int& r_y = x;
 int& r_x = y;

 cout << "Vorher: x= "<< x << " y = " << y << endl;

 swap (x,y);

 cout << "Nachher: x= "<< r_x << " y = " << r_y << endl;

 cin.get();

 return 0;
}