Java 重写小练习

package com.bytezero.inherit3;

public class CylinderTest
{
    public static void main(String[] args) 
    {
        
        Cylinder cy = new Cylinder();
        cy.setRadius(2.2);
        cy.setLength(3.3);
        cy.findVolume();
        System.out.println("圆柱的体积为"+cy.findVolume());
        
        
        //没重写时
//        cy.findArea();
//        System.out.println("圆柱的底面积为"+ cy.findArea());
//        
        //重写以后
        cy.findArea();
        System.out.println("圆柱的表面积为"+ cy.findArea());

        
        
        
        
        
        
    }
}

package com.bytezero.inherit3;

public class Circle 
{
    private double radius;
    
    public Circle()
    {
         this.radius = 1.0;
    }
    

    public void setRadius(double radius)
    {
        this.radius = radius;
    }
    public double getRadius()
    {
        return  radius;
    }
    
    public double findArea()
    {
        return Math.PI * radius*radius;
    }
    
    
    
    
}

package com.bytezero.inherit3;

public class Cylinder extends Circle
{

    private double length;
    
    public Cylinder()
    {
        double length = 1.0;
    }
    
    public void setLength(double length)
    {
        this.length  = length;
    }
    
    
    public double getLength()
    {
        return length;
    }
    
    public double findVolume()
    {
        //return Math.PI * getRadius() * getRadius() *length;
        return Math.PI * getRadius() * getRadius() *getLength();
       // return findArea() * getLength();
        
    }
    
    @Override
    //返回圆柱的表面积
    public double findArea()
    {
        return Math.PI *getRadius() *getRadius() *2+
                2*Math.PI *getRadius()*getLength();
    }
    
    
    
    
}