#include <iostream>  // cout, endl
#include <cstdlib>   // EXIT_SUCCESS

using std::cout;
using std::endl;

void swap(int& x, int& y) {
  int tmp = x;
  x = y;
  y = tmp;
}

int main(int argc, char** argv) {
  int a = 5, b = 10;

  swap(a, b);
  cout << "a: " << a << "; b: " << b << endl;
  return EXIT_SUCCESS;
}