JAVA基础篇—抽象类，抽象方法

class Shape

 package com.shape;

 public abstract class Shape {
     double area;//
     double per;//
     String color;//
     public  Shape() {
     }
     public  Shape(String c){
         this.color=c;
     }
     abstract  double getArea();
     abstract  double getPer();
     abstract  void showAll();
     public  void getColor(String c){
         this.color=c;

     }

 }

class Shape

class Rectangle

 package com.shape;

 public class Rectangle  extends Shape{
     double Width;//
     double height;//

     @Override
     double getArea() {
         return super.area=Width*height;
     }

     @Override
     double getPer() {
         return super.per=Width*+height*;
     }

     @Override
     void showAll() {
         // TODO Auto-generated method stub
         System.out.println("���ε����Ϊ��"+getArea()+"�ܳ�Ϊ"+getPer());
     }
     public Rectangle(){}
     public  Rectangle(double w,double h){
         this.Width=w;
         this.height=h;
     } 

 }

Rectangle

class Circle

 package com.shape;

 public class Circle  extends Shape{
     double radius;//�뾶

     @Override
     double getArea() {
         return super.area=radius*3.14*radius;
     }

     @Override
     double getPer() {
         return super.per=*radius*3.14;
     }

     @Override
     void showAll() {
         // TODO Auto-generated method stub
         System.out.println("Բ�ε����Ϊ��"+getArea()+"�ܳ�Ϊ"+getPer());
     }
     public Circle(double r){
         this.radius=r;
     }
    public Circle(String c){
        this.color=c;

    }
 }

Circle

text

package com.shape;

public class text {
    public static void main(String[] args) {
        Rectangle r=new Rectangle(3.0,4.0);
        r.showAll();
        Circle c=new Circle(5.3);
        c.showAll();
    }
}