Java - Thinking in Java 第8章 习题

1

/**
 * 向上转型
 * <p/>
 * Created by wang on 15/8/7.
 */
class Cycle {
    public void play() {
        System.out.println("Cycle play");
    }
}

class Unicycle extends Cycle{
    @Override
    public void play() {
        System.out.println("Unicycle play");
    }
}

class Bicycle extends Cycle {
    @Override
    public void play() {
        System.out.println("Bicycle play");
    }
}

class Tricycle extends Cycle {
    @Override
    public void play() {
        System.out.println("Tricycle play");
    }
}

public class UpCast {
    public static void ride(Cycle c) {
        c.play();
    }

    public static void main(String[] args) {
        Unicycle u = new Unicycle();
        Bicycle b = new Bicycle();
        Tricycle t = new Tricycle();
        ride(u);
        ride(b);
        ride(t);
    }
}