java大题(7)

return new Hc(x+a.x,y+a.y); }

public Hc add(double a,double b){

return new Hc(x+a,y+b); }

public Hc multiply(Hc a){

return new Hc(x*a.x,y*a.y); }

public Hc multiply(double a,double b){

return new Hc(x*a,y*b); }

public double getvalue(){

return Math.sqrt(x*x+y*y); }

public static void main(String args[]){

Hc x,y,z;

x=new Hc(1,2);

y=new Hc(2,4);

z=x.add(y);

System.out.println(\

z=x.add(4,5);

System.out.println(\

z=x.multiply(y);

System.out.println(\

z=x.multiply(5,6) ;

System.out.println(\

double m=x.getvalue();

System.out.println(x+\的模=\ } }

8(1)定义一个接口，包含一个Display（）方法用于显示信息：通知类，汽车类，广告类??

interface Display{

void display(); }

class Inform implements Display{ public void display(){

System.out.println(\通知内容\ } }

class Car implements Display{ public void display(){

System.out.println(\汽车油亮\ } }

class Adervise implements Display{ public void display(){

System.out.println(\广告消息\ } }

public class Java1{

public static void main(String[]args){

Display []s={new Inform(),new Car(),new Adervise()}; for (int i=0;i

} }

8(2)定义Shape，其中包括一个方法size（），设计矩形、圆、圆柱体等，实现Shape接口。

interface Shape{ double size(); }

class Line implements Shape{ private double x1,y1,x2,y2;

public Line(double x1,double y1,double x2,double y2){ this.x1=x1;this.y1=y1; this.x2=x2;this.y2=y2; }

public double size(){

return Math.sqrt((x2-x1)*(x2-x1)+(y2-y1)*(y2-y1)); } }

class Circle implements Shape{ private double r; public Circle(double r){