#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 x, int y)
{
    int temp;
  
    std::cout << "Swap. Before swap, x: " << x 
              << " y: " << y << "\n";
  
    temp = x;
    x = y;
    y = temp;
  
    std::cout << "Swap. After swap, x: " << x 
              << " y: " << y << "\n";
  
}