text: #include <iostream>
  
  void f(int &y) {
    y = 42;
  }
  
  int main() {
    int x = 41;
    std::cout << "x = " << x << "\n";
    f(x);
    std::cout << "x = " << x << "\n";
    x = 41;
    std::cout << "x = " << x << "\n";
  }
  