circle2.java

《Java面向对象程序设计》例子源代码.轻松学习书本.

//Circle2.java
public class Circle2 extends Point2 {
   private double radius;  
   public Circle2() {
   } 
   public Circle2( int xValue, int yValue, double radiusValue ){
      x = xValue; 			//使用继承自超类Point2的变量x
      y = yValue;			//使用继承自超类Point2的变量y
      setRadius( radiusValue );
   } 
   public void setRadius( double radiusValue ){
      radius = ( radiusValue < 0.0 ? 0.0 : radiusValue );
   } 
   public double getRadius(){
      return radius;
   } 
   public double getDiameter(){
      return 2 * radius;
   } 
   public double getCircumference(){
      return Math.PI * getDiameter();
   } 
   public double getArea(){
      return Math.PI * radius * radius;
   } 
   public String toString(){
   	  //使用继承自超类Point2的变量x和y	
      return "Center = [" + x + ", " + y + "]; Radius = " + radius;
   } 
}