// Fig. 9.10: Circle3.java
// Circle3 class inherits from Point2 and has access to Point2
// protected members x and y.

public class Circle3 extends Point2 {
  private double radius;  // Circle3's radius

  // no-argument constructor
  public Circle3()
  {
    // implicit call to Point2 constructor occurs here
  }

  // constructor
  public Circle3( int xValue, int yValue, double radiusValue )
  {
    // implicit call to Point2 constructor occurs here
    x = xValue;  // no need for validation
    y = yValue;  // no need for validation
    setRadius( radiusValue );
  }

  // set radius
  public void setRadius( double radiusValue )
  {
    radius = ( radiusValue < 0.0 ? 0.0 : radiusValue );
  }

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

  // calculate and return diameter
  public double getDiameter()
  {
    return 2 * radius;
  }

  // calculate and return circumference
  public double getCircumference()
  {
    return Math.PI * getDiameter();
  }

  // calculate and return area
  public double getArea()
  {
    return Math.PI * radius * radius;
  }

  // return String representation of Circle3 object
  public String toString()
  {
    return "Center = [" + x + ", " + y + "]; Radius = " + radius;
  }

} // end class Circle3