上传文件至 'w6'

w6/Main.java

@@ -0,0 +1,37 @@
+abstract class Animal {
+    abstract void makeSound();
+}
+
+interface Swimmable {
+    void swim();
+}
+
+class Dog extends Animal implements Swimmable {
+    public void makeSound() {
+        System.out.println("Woof!");
+    }
+
+    public void swim() {
+        System.out.println("Dog is swimming!");
+    }
+}
+
+class Cat extends Animal {
+    public void makeSound() {
+        System.out.println("Meow!");
+    }
+}
+
+public class Main {
+    public static void main(String[] args) {
+        Animal myDog = new Dog();
+        Animal myCat = new Cat();
+
+        myDog.makeSound();
+        myCat.makeSound();
+
+        if (myDog instanceof Swimmable) {
+            ((Swimmable) myDog).swim();
+        }
+    }
+}