继承、多态（9.22）——————————课后练习

package 课后练习;

/*
 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。
 */

//父类
class Vehicle
{
    //成员属性
    private int wheels ;
    private double weight ;
    
    public int getWheels() {
        return wheels;
    }

    public void setWheels(int wheels) {
        this.wheels = wheels;
    }

    public double getWeight() {
        return weight;
    }

    public void setWeight(double weight) {
        this.weight = weight;
    }

    //构造方法
    public Vehicle( )
    {
        
    }
    
    //成员方法
    public void speak( )
    {
        System.out.println("车轮数量"+wheels+"车重"+weight);
    }
    
}

//子类
class Car extends Vehicle
{
    //成员属性
    private int loader ;
    
    public int getLoader() {
        return loader;
    }

    public void setLoader(int loader) {
        this.loader = loader;
    }

    //构造方法
    public Car( )
    {
        
    }
    
    //成员方法
    public void speak1( )
    {
        System.out.println("载人数"+loader);
    }
}

//子类
class Truck extends Car
{
    //成员属性
    private int payload ;
    
    public int getPayload() {
        return payload;
    }

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

        //构造方法
        public Truck( )
        {
            
        }
        
        //成员方法
        public void speak2( )
        {
            System.out.println("载重量"+payload);
        }
}

//测试类
public class CeshiCar
{

    public static void main(String[] args) 
    {
        Truck a = new Truck( ) ;
        a.setLoader(30);
        a.setPayload(50);
        a.setWeight(10);
        a.setWheels(4);
        a.speak();
        
        a.speak1();
        
        a.speak2();
    }

}

 

package 课后练习;
/*
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，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。
*/

//父类(抽象类)
abstract class Shape
{
    //成员属性
    private double zhouchang ;
    private double mianji ;
    
    public double getZhouchang() {
        return zhouchang;
    }

    public void setZhouchang(double zhouchang) {
        this.zhouchang = zhouchang;
    }

    //构造方法
    public Shape( )
    {
        
    }
    
    //计算周长方法
    public  abstract double zc ( ) ;
    
}

//子类
class Sanjiaoxing extends Shape
{
    private double a ;
    private double  b ;
    private double  c ;
    
    public double getA() {
        return a;
    }

    public void setA(double a) {
        this.a = a;
    }

    public double getB() {
        return b;
    }

    public void setB(double b) {
        this.b = b;
    }

    public double getC() {
        return c;
    }

    public void setC(double c) {
        this.c = c;
    }

    public   double zc ( )
    {
        if ( a+b>c && Math.abs(a-b)<c)
        {
            return a+b+c ;
        }
        else
        {
            return -1 ;
        }
    }
    
    
}

//子类
class Juxing extends Shape
{
    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;
    }

    public Juxing( )
    {
        
    }
    
    public Juxing( double chang,double kuan  )
    {
        this.chang = chang;
        this.kuan = kuan;
    }
    
    public double zc( )
    {
        return (chang+kuan)*2 ;
    }
    
}

//主类
public class CeshiShape {

    public static void main(String[] args) {

        Juxing s = new Juxing( ) ;
         
        s.setChang(2);
        s.setKuan(2);
        System.out.println(s.zc());
    
        Sanjiaoxing x = new Sanjiaoxing( ) ;
         
        x.setA(3);
        x.setB(4);
        x.setC(5);
        
        if(x.zc()==-1)
        {
            System.out.println("不是三角形");
        }
        
        else
        {
        System.out.println(x.zc());
        }
        
        Sanjiaoxing y = new Sanjiaoxing( ) ;
         
        y.setA(1);
        y.setB(1);
        y.setC(2);
        
        if(y.zc()==-1)
        {
            System.out.println("不是三角形");
        }
        
        else
        {
        System.out.println(x.zc());
        }
    }

}

 

package 课后练习;
/*
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。
*/

//父类
class Human
{
    //成员属性
    private String name  ;
    private int age ;
    
    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public void hello( )
    {
        System.out.println(name+"-"+age);
    }
}

//子类
class Man extends Human
{
    //成员属性
    private String sex  ;
    
    public String getSex() {
        return sex;
    }

    public void setSex(String sex) {
        this.sex = sex;
    }

    public void hello1( )
    {
        System.out.println(sex);
    }
}

//子类
class Woman extends Human
{
    //成员属性
    private String sexx  ;
    
    public String getSexx() {
        return sexx;
    }

    public void setSexx(String sexx) {
        this.sexx = sexx;
    }

    public void hello2( )
    {
        System.out.println(sexx);
    }
}

public class Test 
{
    public static void main(String[] args)
    {
        Human a = new Human( ) ;
        a.setName("张三");
        a.setAge(19);
        a.hello();
        
        Man b = new Man( ) ;
        b.setName("李四");
        b.setAge(34);
        b.setSex("我爱跑步");
        b.hello();
        b.hello1();
        
        Woman c = new Woman( ) ;
        c.setAge(22);
        c.setName("王美丽");
        c.setSexx("我爱听音乐");
        c.hello();
        c.hello2();
        
        Human d =new Man() ;
        d.setAge(8);
        d.setName("小明" ) ;
        d.hello( );
        
    }

}

 

package 课后练习;

//接口
public interface ShapePara 
{
    public static final double  PI = 3.14 ;
    public double  getArea( ) ;
    public double getCircumference( ) ;
}

//创建类
 class Circle implements ShapePara
{
    //成员属性
    public double radius ;  //圆的半径
    private double x ;//圆心横坐标
    protected double y ;//圆心纵坐标
    
    //有参构造方法
    Circle(double radius)
    {
        this.radius = radius ;
        x = 0 ;
        y = 0 ;
    }
    
    public double getRadius() {
        return radius;
    }

    public void setRadius(double radius) {
        this.radius = radius;
    }
    
    //成员方法
    public void setCenter(double x, double y)
    {
        this.x = x ;
        this.y = y ;
    }
    
    
    @Override
    public double getCircumference() 
    {
        return 2*PI *radius;
    }

    @Override
    public double getArea()
    {
        return radius*radius*PI;
    }
    
}    

//创建类
abstract class Shape2
{
    public abstract double getArea( ) ;
}

 //子类
class Rect extends Shape2 implements ShapePara
{
    //成员属性
    private double a ;
    private double b ;

    public double getWeight() {
        return a;
    }

    public void setWeight(double weight) {
        this.a = weight;
    }

    public double getHeight() {
        return b;
    }

    public void setHeight(double height) {
        this.b = height;
    }

    @Override
    public double getArea() {
        return a*b ;
    }

    @Override
    public double getCircumference() 
    {
        return (a+b)*2;
    }
    

}

package 课后练习;

public class Ceshitest {

    public static void main(String[] args)
    {
        Circle a = new Circle( 3 ) ;
        ShapePara s = a ;
        System.out.println("圆的周长"+s.getCircumference());
        System.out.println("圆的面积"+s.getArea());
        
        Rect b = new Rect( ) ;
        b.setHeight(2);
        b.setWeight(4);
        ShapePara c = b ;
        System.out.println("矩形面积"+c.getArea());
        System.out.println("矩形周长"+c.getCircumference());
    
    }

}