#include <iostream>

struct holder
{
  holder(int& x) : ref(x) {}

  int& ref;
};

int main() 
{ 
  int x=1, y=3, z=3;

  holder h1(x);
  holder h2(y);
  holder h3(z);

  std::cout << "h1: " << h1.ref << std::endl;
  std::cout << "h2: " << h2.ref << std::endl;
  std::cout << "h2: " << h3.ref << std::endl;

  return 0;
}