public class Main {
    public static void main(String[] args) {
        // 测试多态
        Animal animal1 = new Dog();
        Animal animal2 = new Cat();
        
        System.out.println("Testing polymorphism:");
        animal1.makeSound(); // 应该输出 Woof!
        animal2.makeSound(); // 应该输出 Meow!
        
        // 测试 Dog 的 swim 方法
        System.out.println("\nTesting Dog's swim method:");
        if (animal1 instanceof Swimmable) {
            ((Swimmable) animal1).swim();
        }
        
        // 测试 Cat 是否实现了 Swimmable
        System.out.println("\nTesting if Cat is Swimmable:");
        if (animal2 instanceof Swimmable) {
            ((Swimmable) animal2).swim();
        } else {
            System.out.println("Cat is not Swimmable.");
        }
    }
}