继承类的练习 学习笔记 2

package com.ctgu.java;

public class Circle {
private double radius;

public Circle(){
this.radius = 1;
}

public double getRadius() {
return radius;
}

public void setRadius(double radius) {
this.radius = radius;
}

public double findArea(){
return Math.PI* radius*radius;
}

}
package com.ctgu.java;

public class Cylinder extends Circle {
private double length;

public Cylinder(){
length = 1;
}

public double getLength() {
return length;
}

public void setLength(double length) {
this.length = length;
}

public double findVolume(){
//return Math.PI*this.getRadius()*this.getRadius()*length;
return findArea()*length;
}

}
package com.ctgu.java;

public class TestCylinder {
public static void main(String[] args) {
Cylinder c = new Cylinder();

double area = c.findVolume();
System.err.println(area);
c.setRadius(2.3);
c.setLength(1.2);
area = c.findVolume();
System.out.println(area);
}

}