Duck class

Duck.h

#ifndef DUCK_H_
#define DUCK_H_

class QuackBehavior;

class Duck {
  public:
    Duck(QuackBehavior * quackBehavior);
    virtual ~Duck();

    void quack();
    
    void changeHowToQuack(QuackBehavior * quackBehavior);

  protected:
    QuackBehavior * howToQuack;
};

#endif /* DUCK_H_ */