java上机实验-类.doc

Java上机31 掌握类的继承并应用，要求：（1）定义一个People类, 该类具有类型为double,访问权限是protected的成员变量：height和weight；以及方法：public void speakHello(), public void averageHeight()和public void averageWeight()。（2）定义一个ChinaPeople类, ,它是People的子类，新增了public void chinaGongfu()方法,并要求ChinaPeople类重写父类的public void speakHello(), public void averageHeight()和public void averageWeight()方法。（3）定义一个BeijingPeople类, ,它是ChinaPeople的子类，新增了public void beijingOpera()方法,并要求BeijingPeople类重写父类的public void speakHello(), public void averageHeight()和public void averageWeight()方法。（4）定义一个主类，在主类中用上述类生成对象以及使用对象。class People protected double height; protected double weight; public void speakHello() System.out.println(Hello,我是people类！); public void averageHeight() height=165; System.out.println(people平均身高为+height+厘米); public void averageWeight() weight=150; System.out.println(people平均体重为+weight+斤); class ChinaPeople extends People public void chinaGongfu() System.out.println(I like chinese gongfu!); public void speakHello() System.out.println(Hello,我是ChinaPeople类！); public void averageHeight() height=175; System.out.println(ChinaPeople平均身高为+height+厘米); public void averageWeight() weight=145; System.out.println(ChinaPeople平均体重为+weight+斤); class BeijingPeople extends ChinaPeople public void beijingOpera() System.out.println(我会唱京剧!); public void speakHello() System.out.println(Hello,我是BeijingPeople类！); public void averageHeight() height=168; System.out.println(BeijingPeople平均身高为+height+厘米); public void averageWeight() weight=148; System.out.println(BeijingPeople平均体重为+weight+斤); public class E31 public static void main(String args) People people=new People(); ChinaPeople chinapeople=new ChinaPeople(); BeijingPeople beijingpeople=new BeijingPeople(); people.speakHello(); people.averageHeight(); people.averageWeight(); chinapeople.chinaGongfu(); chinapeople.speakHello(); chinapeople.averageHeight(); chinapeople.averageWeight(); beijingpeople.chinaGongfu(); beijingpeople.beijingOpera(); beijingpeople.speakHello(); beijingpeople.averageHeight(); beijingpeople.averageWeight(); 2 掌握抽象类的应用，要求：定义抽象类Shape，有2个抽象方法为showArea()、showzc()，分别求出面积、周长并显示，定义其子类正方形类Square,圆类 Circle，定义各自类的属性，用showArea方法、showzc()方法求出各自的面积、周长。定义主类，并在main方法中构造2个对象，调用showArea方法、showzc()方法。abstract class Shapeabstract double showArea(); abstract double showzc();class Square extends Shapedouble a,b;Square(double a,double b) /构造方法this.a=a;this.b=b; double showArea()return (a*b); double showzc()return(a*b)*2;class Circle extends Shapedouble r;Circle(double r) /构造方法this.r=r; double showArea()return(3.14*r*r); double showzc() return 2*3.14*r;public class t2public static void main(String args) Square square=new Square(10,10); /有参构造Circle circle = new Circle(2);System.out.println(边长为”+a+”的正方形的面积为：”+square.showArea();System.out.println(正方形的周长为：+square.showzc();System.out.println(半径为”+r+”的圆的面积为：+circle.showArea();System.out.println(圆的周长为：+circle.showzc();3掌握接口的应用，要求：设计一个程序可以计算平面图形的面积。（1）使用interface关键字定义Shape接口，接口中包含一个求解面积的方法；（2）使用extends从接口Shape派生出接口Shape2D，并为接口Shape2D添加一个求解周长的方法定义； （3）编写一个正方形类Square，该类实现Shape2D接口； (4)定义一个Scaleable接口，该接口中定义一个scale（double proportion）方法；(5) 编写一个可缩放的正方形SquareScaleable类，该类继承于Square类同时实现Scaleable接口；（6）定义主类，在主类中生成SquareScaleable类的若干对象，并计算其缩放前后的面积和周长。interface Shapedouble showArea();interface Shape2D extends Shapedouble showzc();class Square implements Shape2Ddouble a;Square (double a)this.a = a;public double showArea() return a*a;public double showzc() return 4*a;interface Scaleablevoid scale(double proportion);class SquareScaleable extends Square implements ScaleableSquareScaleable(double a) super(a);public void scale(double proportion) a=a*proportion;public class t3 public static void main(String args)SquareScaleable square = new SquareScaleable(3);System.out.println(square边