#include <iostream>
using namespace std;

void foo(int x, int y) {
  x = 3;
  cout << "1: " << x * y << endl;
}

void bar(int & x, int & y) {
  x = 3;
  cout << "2: " << x * y << endl;
}

int main(int argc, char **argv) {
  int a,b;
  a = 2;
  b = 2;

  foo(a,a);
  bar(b,b);

  cout << "end: " << a << "," << b << endl;

  return 0;
}

// Lala:Desktop jeena$ ./a.out
// 1: 6
// 2: 9
// end: 2,3