#include <iostream>
  
void swap(int &x, int &y);

int main()
{
    int x = 5, y = 10;
  
    std::cout << "Main. Before swap, x: " << x 
              << " y: " << y << "\n";
    swap(x, y);
    std::cout << "Main. After swap, x: " << x 
              << " y: " << y << "\n";
    return 0;
}
  
void swap(int &rx, int &ry)
{
    int temp;
  
    std::cout << "Swap. Before swap, rx: " << rx 
              << " ry: " << ry << "\n";
  
    temp = rx;
    rx = ry;
    ry = temp;
  
    std::cout << "Swap. After swap, rx: " << rx 
              << " ry: " << ry << "\n";
}