Merge branch 'main' of http://git.innoschool.org:3000/WangJunyue/java

Animal.java

@@ -0,0 +1,34 @@
+abstract class Animal {
+    public abstract void makesound();
+}
+interface Swimmable{
+    void swim();
+}
+class Dog extends Animal implements Swimmable{
+    @Override
+    public void makesound(){
+        System.out.println("汪汪汪");
+    }
+    @Override
+    public void swim(){
+        System.out.println("狗刨游泳");
+    }
+}
+class Cat extends Animal{
+    @Override
+    public void makesound(){
+        System.out.println("喵喵喵");
+    }
+}
+class Main{
+    public static void main(String[]args){
+        Animal a =new Dog();
+        Animal b =new Cat();
+        a.makesound();
+        b.makesound();
+        if (a instanceof Swimmable){
+            ((Swimmable)a).swim();
+        }
+    }
+}
+