circle.java

java 的几个比较不错的有代表性的案例的源码

/**
 * Circle.java
 */

public class Circle extends Point {
  protected double radius;

  public Circle() {
    super(0,0);
    setRadius(0);
  }

  public Circle(double r,double a,double b) {
    super(a,b);
    setRadius(r);
  }

  public void setRadius( double r){
    radius = (r>=0.0?r:0.0);
  }

  public double getRadius(){
    return radius;
  }

  public double area(){
    return 3.1415926 * radius *radius;
  }

  public String toString(){
    return "Center = "+
        super.toString()+"; Radius= "+radius;
  }
}