public abstract class AinmalSound {
    public abstract void makeSound();
}
interface Swimmable{
    void swim();
}
class Cat extends AnimalSound {
    @Override
    public void makeSound() {
        System.out.println("猫：喵喵喵！");
    }
}
class Dog extends AnimalSound implements Swimmable {
    @Override
    public void makeSound() {
        System.out.println("狗：汪汪汪！");
    }
    @Override
    public void swim() {
        System.out.println("狗：我会游泳！");
    }
}