interface Pet { public abstract void play(); }

​

class Cat implements Animal, Pet {

    public void cry() {

        System.out.println("냐옹냐옹!");

    }

    public void play() {

        System.out.println("나비야~ 쥐 잡기 놀이하자~!");

    }

}

​

class Dog implements Animal, Pet {

    public void cry() {

        System.out.println("멍멍!");

    }

    public void play() {

        System.out.println("바둑아~ 산책가자~!");

    }

}

​

public class prog {

    public static void main(String[] args) {

        Cat c = new Cat();

        Dog d = new Dog();

        c.cry();

        c.play();

        d.cry();

        d.play();

    }

}