struct DuckInterface {
  virtual string Quack() = 0;
}

struct DuckListener {
  void Listen(DuckInterface& d) {
    cout << "the duck quacks like this " << d.Quack() << endl;
  }
}

struct Dog {
  void Quack {
    return "woof";
  }
}

struct DogToDuckAdapter : DuckInterface {
  DogToDuckAdapter(Dog* x) : m(x) { }
  virtual string Quack() { return m->Quack(); }
  Dog* m;
}

int main() {
  Dog dog;
  DuckListener listener;  
  DogToDuckAdapter ducklike(&dog);
  listener.Listen(ducklike);
}

template<typename T>
struct GenericDuckAdapter : DuckInterface {
  GenericDuckAdapter(T* x) : m(x) { }
  virtual string Quack() { return m->Quack(); }
  T* m;
}

int main() {
  Dog dog;
  DuckListener listener;
  GenericDuckAdapter<dog> ducklike(&dog); 
  listener.Listen(ducklike);
}