public abstract class EquidistantShape {
  private double theRadius;

  public void setRadius(double newRadius) {
    if (newRadius >= 0.0) {
      theRadius = newRadius;
    }  // end if
  }  // end setRadius

  public double radius() {
    return theRadius;
  }  // end radius

  public abstract void displayStatistics();
}  // end EquidistantShape