11java基础继承

一、           继承相关

 

18．实现如下类之间的继承关系，并编写Music类来测试这些类。

package com.hry.test;

public class Instrument {

    //输出弹奏乐器
    public void play()
    {
        System.out.println("弹奏乐器");
    }
}

package com.hry.test;

public class Wind extends Instrument {
    //输出"弹奏wind"
    public void play()
    {
        System.out.println("弹奏wind");
    }
    //输出"调用wind的play2"
    public void play2()
    {
        System.out.println("调用wind的play2");
    }

}

package com.hry.test;

public class Brass extends Instrument {
    //输出"弹奏brass"
    public void play()
    {
        System.out.println("弹奏brass");
    }
    //输出"调用brass的play2"
    public void play2()
    {
        System.out.println("调用brass的play2");
    }

}

package com.hry.test;

public class Music {

        //调用对象i的play方法

        //调用tune方法，以Wind类对象为参数
        ////调用tune方法，以Brass类对象为参数
            public static void tune(Instrument i){
                i.play();
            }
                public static void main(String[] args)
                 {
                    Instrument i= new Instrument();
                    i.play();
                    Wind w= new Wind();
                    w.play();
                    w.play2();

                    Brass b= new Brass();
                    b.play();
                    b.play2();
               }

}

19．创建如下三个类：（People类中的三个方法分别输出一些信息，ChinaPeople

和AmericanPeople类重写父类的三个方法）。

package  com.hry.test;;

public class People {
    protected double height;
    protected double weight;
    public double getHeight() {
        return height;
    }
    public void setHeight(double height) {
        this.height = height;
    }
    public double getWeight() {
        return weight;
    }
    public void setWeight(double weight) {
        this.weight = weight;
    }

    public void speakHello()
    {
    }
    public void averageHeight()
    {
    }
    public void averageWeight()
    {
    }

}

package com.hry.test;

public class ChinaPeople extends People{
    public void chinaGoufu()
    {
        System.out.println("少林、太极、咏春拳");
    }
    public void speakHello()
    {
        System.out.println("中文");
    }
    public void averageHeight()
    {
        System.out.println("中国人平均身高为175cm");
    }
    public void averageWeight()
    {
        System.out.println("中国人平均体重是65kg");
    }

}

package com.hry.test;

public class AmericnPeople extends People{
    public void chinaGoufu()
    {
        System.out.println("直拳");
    }
    public void speakHello()
    {
        System.out.println("英文");
    }
    public void averageHeight()
    {
        System.out.println("美国人平均身高为180cm");
    }
    public void averageWeight()
    {
        System.out.println("美国人平均体重是70kg");
    }

}

package com.hry.test;

public class TestPeople {

    public static void main(String[] args) {

        ChinaPeople c =new ChinaPeople();
        c.speakHello();
        c.averageHeight();
        c.averageWeight();

        AmericnPeople a=new AmericnPeople();
        a.speakHello();
        a.averageHeight();
        a.averageWeight();

}
}

 

21．编写一个Java应用程序，该程序包括3个类：Monkey类、People类和主类

E。要求：

(1) Monkey类中有个构造方法：Monkey (String s)，并且有个public void speak()

方法，在speak方法中输出“咿咿呀呀......”的信息。

(2)People类是Monkey类的子类，在People类中重写方法speak(),在speak方法

中输出“小样的，不错嘛！会说话了！”的信息。

(3)在People类中新增方法void think()，在think方法中输出“别说话！认真思考！”

的信息。

(4)在主类E的main方法中创建Monkey与People类的对象类测试这2个类的功

能。

package com.hry.test;

public class Monkey {

    Monkey(String s)  //构造
    {}

    public void speak()
    {
        System.out.println("咿咿呀呀......");
    }
}

package com.hry.test;

public class People1 extends Monkey{

    People1(String s) {
        super(s);
        // TODO 自动生成的构造函数存根
    }

    public void speak()
    {
        System.out.println("小样的，不错嘛！会说话了！");
    }
    public void think()
    {
        System.out.println("别说话！认真思考！");
    }

}

package com.hry.test;

public class E1 {

    public static void main(String[] args) {
        // TODO 自动生成的方法存根

        Monkey m = new Monkey("tom");
        m.speak();

        People1 p = new People1("Xiaoming");
        p.speak();
        p.think();

    }

}