import cs1.Keyboard;
/**
   A simple Circle defined by a radius.
   @author Greg Vogl
   last modified 2003-10-06
*/
public class Circle
{
   public Circle() { radius = 1; }
   public Circle(double radius) { this.radius = radius; }
   public double radius() { return radius; }
   public double diameter() { return 2 * radius; }
   public double circumference() { return 2 * Math.PI * radius; }
   public double area() { return Math.PI * radius * radius; }
   public String toString()
   {
      return "Circle" + 
         "[radius=" + radius() + 
         ",diameter=" + diameter() + 
         ",circumference=" + circumference() + 
         ",area=" + area() + 
         "]";
   }
   private double radius;
}