完全不知道怎么办，太可恶了

完全读不懂，太绕了，怎么写都报错，根本就是伪命题，怎么会这样

我来写，确实有些绕，但按题目的要求也是可以写出来的，你看看我写的是否符合题目的要求，有帮助的话采纳一下哦！我想令你迷惑的是，在哪个类中创建一个SoundMachine对象吧！因为他没写什么类，但根据后面说，创建了一个我们就可以推断出，他应该在测试类中比较合理。

Test.java

package Music;

public class Test {
    public static void main(String[] args) {
        SoundMachine sou = new SoundMachine();
        Violin s1 = new Violin();
        Piano s2 = new Piano();
        sou.play(s1);
        sou.play(s2);
    }
}

// Sound接口
interface Sound {
    void makeSound();
}

// SoundMachine类
class SoundMachine {
    public SoundMachine() {
    }
    void play(Sound sound){
        sound.makeSound();
    }
}

// 小提琴类
class Violin implements Sound{
    @Override
    public void makeSound() {
        System.out.println("小提琴的声音");
    }
}

//钢琴类
class Piano implements Sound{
    @Override
    public void makeSound() {
        System.out.println("钢琴的声音");
    }
}

interface Sound {
  public void makeSound();
}

class SoundMachine{
  public void play(Sound sound) {
    sound.makeSound();
  }
}

class Piano implements Sound{
  public void makeSound(){
    System.out.println("钢琴的声音");
  }
}

class Violin implements Sound{
  public void makeSound(){
    System.out.println("小提琴的声音");
  }
}

public class Main{
  public static void main(String[] args) {
    SoundMachine machine = new SoundMachine();
    Violin violin = new Violin();
    Piano piano = new Piano();
    machine.play(violin);
    machine.play(piano);
  }
}

建议题主可以自己先动动手哦，把接口，实现，方法重写这些知识先掌握了。这是java的基础知识，把基础打牢。

看看吧，大概就是这样的，不懂的再问

public interface Sound {
    public void makeSound();
}

public class SoundMachine {
    public void play( Sound sound){
        sound.makeSound();
    }
}

public class PianoSound implements Sound{
    @Override
    public void makeSound() {
        System.out.println("钢琴的声音");
    }
}

public class  ViolinSound implements Sound{

    @Override
    public void makeSound() {
        System.out.println("小提琴的声音");
    }
}

public class Main {
    public static void main(String[] args) {
        PianoSound pianoSound =new PianoSound();
        ViolinSound violinSound =new ViolinSound();
        SoundMachine soundMachine =new SoundMachine();
        soundMachine.play(pianoSound);
        soundMachine.play(violinSound);
    }
}

我给你写

package com.example.demo003.test;

interface Sound {
    void makeSound();
}

class XiaoTiqin implements Sound {
    @Override
    public void makeSound() {
        System.out.println("小提琴的声音");
    }
}

class Gangqin implements Sound {
    @Override
    public void makeSound() {
        System.out.println("钢琴的声音");
    }
}


public class SoundMachine {
    void play(Sound sound) {
        sound.makeSound();
    }

    public static void main(String[] args) {
        final Sound xiaoTiqin = new XiaoTiqin();
        final Sound gangqin = new Gangqin();
        final SoundMachine soundMachine = new SoundMachine();
        soundMachine.play(xiaoTiqin);
        soundMachine.play(gangqin);
    }
}