#include <iostream>

class ICar {
public:
  virtual void DriveCar() = 0;
};

class Car : public ICar {
  void DriveCar() override {
    std::cout << "Car has been driven!";
  }
};

class ProxyCar : public ICar {
private:
  ICar* realCar = new Car();
  int _driver_age;

public:
  ProxyCar (int driver_age) : _driver_age(driver_age) {}

  void DriveCar() {  
    if (_driver_age > 16)
      realCar->DriveCar();
    else
      std::cout << "Sorry, the driver is too young to drive.";
  }
};

//How to use above Proxy class? 
int main()
{
  ICar* car = new ProxyCar(16);
  car->DriveCar();
    
  delete car;

  car = new ProxyCar(25);
  car->DriveCar();
    
  delete car;

  return 0;
}