circle.java

Java程序设计技巧与开发实例附书源代码。

public class Circle extends Shape
{  protected double radius;
    public Circle(double _radius)
   {  name = "Circle";
        radius = _radius;
     }
   public void computeArea()
     {  area = Math.PI * radius * radius; }
   public void computePerimeter()
    {  perimeter = 2 *Math.PI * radius; }
}