0922继承，练习题目-作业

 

1.实现如下类之间的继承关系，并编写Music类来测试这些类。

 

package workhome0922休息;

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;
	}
	//方法
	public void speakHello()
	{
		System.out.print("我是一个人"+"  ");
	}
	public void averageHeight()
	{
		System.out.print("我有身高"+"  ");
	}
	public void averageWeight()
	{
		System.out.println("我有体重"+"  ");
	}
	
}


package workhome0922休息;

public class ChinaPeople extends People {

	public void speakHello()
	{
		System.out.print("中国人"+"  ");
	}
	public double averageHeight(double height)
	{
//		return height;
		this.height=height;//为什么要把height赋给父类的height？？？？？？
		return this.height;	
	}
	public double averageWeight(double weight)
	{
		this.weight=weight;
		return this.weight;
		
	}
	public void chinaGongFu()
	{
		System.out.println("中国功夫"+"太极拳");
	}
}

package workhome0922休息;

public class AmericanPeople extends People {

	public void speakHello()
	{
		System.out.print("美国人");
	}
	public double averageHeight(double height)
	{
		this.height=height;
		return this.height;
	}
	public double averageWeight(double weight)
	{
		this.weight=weight;
		return this.weight;
	}
	public void americanBoxing()
	{
		System.out.println("美国功夫："+"直拳");
	}
}

package workhome0922休息;

public class Peopletest {

	public static void main(String[] args) {
		//实例化人
		People p=new People();
		p.speakHello();
		p.averageHeight();
		p.averageWeight();
		//实例化中国人
		ChinaPeople c=new ChinaPeople();
		c.speakHello();
		System.out.print(""+"身高:"+c.averageHeight(171.2));
		System.out.print("  "+"体重:"+c.averageWeight(125)+"  ");
		c.chinaGongFu();
		//实例化美国人
		AmericanPeople a=new AmericanPeople();
		a.speakHello();
		System.out.print("  "+"身高:"+a.averageHeight(180));
		System.out.print("  "+"体重:"+a.averageWeight(160)+"  ");
		a.americanBoxing();
		
	}

}

2.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 workhome0922休息;

public class Instrument {
	//方法-输出:弹奏乐器
	public void play()
	{
		System.out.println("弹奏乐器");
	}
}


package workhome0922休息;

public class Wind extends Instrument {
	//方法1-输出：弹奏Wind
	public void play()
	{
		System.out.println("弹奏Wind");
	}
	//方法2-输出：调用Wind的play2
	public void play2()
	{
		System.out.println("调用Wind的play2");
	}

}

package workhome0922休息;

public class Brass extends Instrument {

	//方法1-输出：弹奏brass
	public void play()
	{
		System.out.println("弹奏brass");
	}
	//方法2-输出：调用brass的play2
	public void play2()
	{
		System.out.println("调用brass的play2");
	}
}


package workhome0922休息;

public class Music {

	//调用对象i的play方法
	public static void tune(Instrument i)
	{
		i.play();
	}	
	public static void main(String[] args) {
		
		Wind w=new Wind();
		Music.tune(w);
		w.play2();
		Brass b=new Brass();
		Music.tune(b);
	}
}

3.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 workhome2;

public class Monkey {

	//构造方法
	Monkey(String s)
	{
		super();
		System.out.println(s+1);
	}
	Monkey(int ss)
	{
		System.out.println(ss);
	}
	//方法
	public void speak()
	{
		System.out.println("咿咿呀呀......");
	}
}


package workhome2;

public class People extends Monkey {

	//继承构造方法
	public People(String s) {
		super(s);
		System.out.println(s+10);
		
	}
	//重写父类方法speak
	public void speak()
	{
		System.out.println("小样的，不错嘛！会说话了");
	}
	//新增方法
	public void think()
	{
		System.out.println("别说话！认真思考！");
	}
}


package workhome2;

public class E {

	public static void main(String[] args) {

		//创建Monkey对象
		Monkey m=new Monkey("10");
		m.speak();
		//创建People对象
		People p=new People("10");
		p.speak();
		p.think();

	}

}

4.定义类Human，具有若干属性和功能；定义其子类Man、Woman；

在主类Test中分别创建子类、父类和上转型对象，并测试其特性。

 

package workhome3;

public class Human {
	//人的属性
	public String leg;
	public String foot;
	public String getLeg() {
		return leg;
	}
	public void setLeg(String leg) {
		this.leg = leg;
	}
	public String getFoot() {
		return foot;
	}
	public void setFoot(String foot) {
		this.foot = foot;
	}
	//人的方法
	public void run()
	{
		System.out.println("可以跑");
	}
	public void jump()
	{
		System.out.println("可以跳");
	}
	public int Int(int a)
	{
		a=a+1;
		return a;
	}
}



package workhome3;

public class Man extends Human {

	//男人的方法
		public void run()
		{
			System.out.println("可以跑快");
		}
		public void jump()
		{
			System.out.println("可以跳高");
		}
		public void eat()
		{
			System.out.println("吃饭睡觉打豆豆");
		}
	
}



package workhome3;

public class Woman extends Human {

	//女人的方法
	public void run()
	{
		System.out.println("可以跑慢");
	}
	public void jump()
	{
		System.out.println("可以跳矮");
	}
}




package workhome3;

public class humantest {

	public static void main(String[] args) {
		
		//向上转型
		Human h1=new Man();
		h1.setFoot("人有两条腿");
		System.out.println(h1.getFoot());
		h1.run();
		System.out.println(h1.Int(10));
		//向下转型
		Man m1=(Man)h1;
		m1.setFoot("男人有两条比女人长的腿");
		System.out.println(m1.getFoot());
		m1.jump();
		System.out.println(m1.Int(10));
		m1.eat();

	}

}

6.按要求编写一个Java应用程序：

（1）定义一个类，描述一个矩形，包含有长、宽两种属性，和计算面积方法。

（2）编写一个类，继承自矩形类，同时该类描述长方体，具有长、宽、高属性，和计算体积的方法。

（3）编写一个测试类，对以上两个类进行测试，创建一个长方体，定义其长、宽、高，输出其底面积和体积。

 

package workhome4;

public class jivxing {
//	包含有长、宽两种属性，和计算面积方法。
	private double chang;
	private double kuan;
	public double getChang() {
		return chang;
	}
	public void setChang(double chang) {
		this.chang = chang;
	}
	public double getKuan() {
		return kuan;
	}
	public void setKuan(double kuan) {
		this.kuan = kuan;
	}
	//方法
	public double mianji(double chang,double kuan)
	{
		this.chang=chang;
		this.kuan =kuan;
		return this.chang*this.kuan;
	}
}


package workhome4;

public class jivxing2 extends jivxing {
	private double gao;
	
	public double getGao() {
		return gao;
	}

	public void setGao(double gao) {
		this.gao = gao;
	}

	public double tiji(double chang,double kuan,double gao)
	{
		this.gao=gao;
		return super.mianji(chang, kuan)*this.gao;
		
	}

}



package workhome4;

public class test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		jivxing2 j=new jivxing2();
		System.out.println(j.mianji(1, 2));
		System.out.println(j.tiji(1, 2, 3));

	}

}

7.　

编写一个Java应用程序，设计一个汽车类Vehicle，包含的属性有车轮个数

wheels和车重weight。小车类Car是Vehicle的子类，其中包含的属性有载人数

loader。卡车类Truck是Car类的子类，其中包含的属性有载重量payload。每个

类都有构造方法和输出相关数据的方法。最后，写一个测试类来测试这些类的功

能。

 

package workhome4;

public class Vehicle {
	//wheels和车重weight
	private int wheel;//轮胎数量
	private double weight;//车重
	
	public int getWheel() {
		return wheel;
	}
	public void setWheel(int wheel) {
		this.wheel = wheel;
	}
	public double getWeight() {
		return weight;
	}
	public void setWeight(double weight) {
		this.weight = weight;
	}
	//构造方法
	public Vehicle(int wheel,double weight)
	{
		super();
		this.wheel=wheel;
		this.weight=weight;
		
	}
	//方法
	public void vv()
	{
		System.out.print("轮胎数："+this.wheel+"  "+"车重："+this.weight+"  ");
	}

}


package workhome4;

public class Car extends Vehicle {

	
	private int loader;//载人数
	public int getLoader() {
		return loader;
	}
	public void setLoader(int loader) {
		this.loader = loader;
	}
	public Car(int wheel,double weight,int loader) {
		super(wheel,weight);
		this.loader=loader;
		
	}
	//方法
	public void cc()
	{
		System.out.println();
		super.vv();
		System.out.print("和载人数"+this.loader+"  ");
	}
	
}


package workhome4;

public class Truck extends Car {

	private double payload;//载重量

	public double getPayload() {
		return payload;
	}

	public void setPayload(double payload) {
		this.payload = payload;
	}

	public Truck(int wheel, double weight, int loader, double payload) {
		super(wheel, weight, loader);
		this.payload=payload;
	}
//方法
	public void tt()
	{
		super.cc();
		System.out.println("载重量"+this.payload+"  ");
	}
	
	
}


package workhome4;

public class cartest {
	public static void main(String[] args) {
			Vehicle v=new Vehicle(4,99999);
			v.vv();
			Car c=new Car(4,888888,3);
			c.cc();
			Truck t=new Truck(4,777777,6,90000.888);
			t.tt();
	
	}		
}

8.编写一个Shape类，具有属性：周长和面积；

定义其子类三角形和矩形，分别具有求周长的方法。

定义主类E，在其main方法中创建三角形和矩形类的对象，

并赋给Shape类的对象a、b，使用对象a、b来测试其特性。

 

package workhome5;

public interface Shape {
	public abstract void zc(int a,int b,int c);
	public abstract void mj(int a,int b,int c);

}


package workhome5;

public class sanjiaoxing implements Shape {

	@Override
	public void zc(int a,int b,int c) {
		// TODO Auto-generated method stub
		System.out.println("三角形的周长为："+(a+b+c));
	}

	@Override
	public void mj(int a,int b,int c) {
		// TODO Auto-generated method stub
		System.out.println("三角形的面积为："+a*b/2);
	}

}


package workhome5;

public class jvxing implements Shape {

	@Override
	public void zc(int a, int b,int c) {
		// TODO Auto-generated method stub
		System.out.println("矩形的周长为："+(a+b)*2);

	}

	@Override
	public void mj(int a, int b, int c) {
		// TODO Auto-generated method stub
		System.out.println("矩形的面积为："+2*(a+b));
	}

}

package workhome5;

public class cheng {

	private Shape i;

	public Shape getI() {
		return i;
	}

	public void setI(Shape i) {
		this.i = i;
	}
	public void getit()
	{
		i.mj(3, 2, 1);
		i.zc(3, 2, 1);
	}
}


package workhome5;

public class test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub

		cheng v=new cheng();
		sanjiaoxing a=new sanjiaoxing();
		v.setI(a);
		v.getit();
		jvxing b=new jvxing();
		v.setI(b);
		v.getit();
	}

}

　　

 

　9.

package jiekouhomework;

public interface ShapePara {
//	nt getArea()：获得图形的面积。int getCircumference()：获得图形的周长
	public abstract double getArea();
	public abstract double getCircumference();
}



package jiekouhomework;

public class Circle implements ShapePara {

//	adius:public 修饰的double类型radius,表示圆的半径。
//	x：private修饰的double型变量x，表示圆心的横坐标。
//	y：protected修饰的double型变量y，表示圆心的纵坐标。
	public double radius;
	private double x;
	protected double y;
	double PI=3.14;
	
	public double getRadius() {
		return radius;
	}

	public void setRadius(double radius) {
		this.radius = radius;
	}

//	public double getX() {
//		return x;
//	}
//
//	public void setX(double x) {
//		this.x = x;
//	}
//
//	public double getY() {
//		return y;
//	}
//	public void setY(double y) {
//		this.y = y;
//	}
	
	//构造方法
	Circle(double radius) 
	{
		this.radius=radius;
	}
	//方法
	public void setCenter(double x, double y)
	{
		this.x=x;
		this.y=y;
	}

	@Override
	public double getArea() {
		// TODO Auto-generated method stub
//		System.out.println(PI*radius*radius);
		
		return PI*this.radius*this.radius;
	}

	@Override
	public double getCircumference() {
		// TODO Auto-generated method stub
//		System.out.println(2*PI*this.radius);
		return 2*PI*this.radius;
	}


package jiekouhomework;

public class jiehe {
	private ShapePara s;

	public ShapePara getS() {
		return s;
	}

	public void setS(ShapePara s) {
		this.s = s;
	}
	public void ceshi()
	{
		s.getArea();
		s.getCircumference();
	}

}


package jiekouhomework;

public class test {

	public static void main(String[] args) {
		// TODO Auto-generated method stub
		
		jiehe ss=new jiehe();
		Circle cc=new Circle(7);
		ss.setS(cc);

　　　　　　　　　System.out.println(cc.getArea());
　　　　　　　　System.out.println(cc.getCircumference());

	}

}