class Car float getCost virtual void addEngine Engine engine class Car

class Car
{
...
  float getCost();
  virtual void addEngine(Engine* engine);
...
};

class CarDecorator
{
protected:
  Car* mCar;
public:
  CarDecorator(Car* car) : mCar(car) {};
  void setCar(Car* car) {mCar = car;}
...
  virtual float getCost() {return mCar->getCost();}
  virtual void addEngine(Engine* engine) {mCar->addEngine(engine);}
...
};