/**
   A circle with a center and radius.
   @author Greg Vogl
   last modified 2003-10-14
*/
public class CircleShape extends Shape
{
   // constructors
   // override defaults
   public CircleShape() { super(); radius = 1; }
   public CircleShape(double x, double y) { super(x, y); radius = 1; }

   // additional constructors
   public CircleShape(double radius) { super(); this.radius = radius; }
   public CircleShape(double x, double y, double radius) 
      { super(x, y); this.radius = radius; }

   // accessor
   public double getRadius() { return radius; }

   // calculations
   public double perimeter() { return 2 * Math.PI * radius; }
   public double area() { return Math.PI * radius * radius; }

   // toString
   public String toString()
   {
      return super.toString() + "[radius=" + radius + "]";
   }

   // private variables
   private double radius;
}