/** Inheritance demo.
    @author Jed Yang, 2017-04-03
*/
public class Circle extends Shape
{
   // instance variables, private
//   private String name;
   private int radius;

   public Circle(String name, int radius)
   {
      super(name);
      this.radius = radius;
   }

   public Circle()
   {
      this("circle", 10);
   }

   public double getArea()
   {
      return Math.PI * Math.pow(radius, 2);
   }

   public double getPerimeter()
   {
      return 2 * Math.PI * radius;
   }

   // Often automatically called.  Like Python's __str__ magic method.
   public String toString()
   {
      return super.toString() + " of radius " + radius;
   }
}