public class Circle extends EquidistantShape {
   public Circle() {
      setRadius(1.0);
   } // end default constructor

   public Circle(double initialRadius) {
      setRadius(initialRadius);
   } // end constructor

   // Implementation of abstract method
   public void displayStatistics() {
      System.out.println("\nRadius = " + radius()
         + "\nDiameter = " + diameter()
         + "\nCircumference = " + circumference()
         + "\nArea = " + area());
   } // end displayStatistics

   public double diameter() {
      return 2 * radius();
   }

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

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

} // end Circle