public class Main {
    public static void main(String[] args){
        Animal dog = new Dog();
        Animal cat = new Cat();

        System.out.println("动物叫声");
        dog.makeSound();
        cat.makeSound();

        System.out.println("是否会游泳");
        if (dog instanceof Swimmable){
            ((Swimmable) dog).swim();
        }
        if (cat instanceof Swimmable){
            ((Swimmable) cat).swim();
        } else {
            System.out.println("猫不会游泳");
        }
    }
}