上传文件至 'w6'

w6/Animal.java

@@ -0,0 +1,5 @@
+package Sound;
+
+public abstract class Animal {
+    public abstract void makeSound();
+}

w6/Cat.java

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+package Sound;
+
+public class Cat extends Animal{
+    @Override
+    public void makeSound(){
+        System.out.println("喵喵");
+    }
+}

w6/Dog.java

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+package Sound;
+
+public class Dog extends Animal implements Swimmable{
+    @Override
+    public void makeSound(){
+        System.out.println("汪汪");
+    }
+    @Override
+    public void swim(){
+        System.out.println("小狗在游泳");
+    }
+}

w6/Main.java

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+package Sound;
+
+public class Main{
+    public static void main(String[] args){
+        Animal dog = new Dog();
+        Animal cat = new Cat();
+
+        dog.makeSound();
+        cat.makeSound();
+
+        Dog myDog = new Dog();
+        myDog.swim();
+    }
+}

w6/Swimmable.java

@@ -0,0 +1,5 @@
+package Sound;
+
+public interface Swimmable {
+    public abstract void swim();
+}