public MallardDuck() { // 这里有问题? 对实现进行了编程. // program to an implementation. // 可以在运行时切换方法. _quackBehavior = new Quack(); _flyBehavior = new FlyWithWings(); }
public ModelDuck() { _flyBehavior = new FlyNoWay(); _quackBehavior = new Quack(); }
public MallardDuck() { quackBehavior = new Quack(); flyBehavior = new FlyWithWings(); }