java/w6/Animal.java

abstract class Animal {
    public abstract void makeSound();
}

interface Swimmable {
    void swim();
}

class Dog extends Animal implements Swimmable {
    @Override
    public void makeSound() {
        System.out.println("🐶 汪汪汪！（Dog叫声）");
    }

    @Override
    public void swim() {
        System.out.println("🐶 狗狗在水中快乐地游泳～");
    }
}


class Cat extends Animal {
    @Override
    public void makeSound() {
        System.out.println("🐱 喵喵喵！（Cat叫声）");
    }

}