// Fig. 9.6: Circle.java
// Circle class contains x-y coordinate pair and radius.

public class Circle {
  private int x;          // x-coordinate of Circle's center
  private int y;          // y-coordinate of Circle's center
  private double radius;  // Circle's radius

  // no-argument constructor
  public Circle()
  {
    // implicit call to Object constructor occurs here
  }

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

  // set x in coordinate pair
  public void setX( int xValue )
  {
    x = xValue;  // no need for validation
  }

  // return x from coordinate pair
  public int getX()
  {
    return x;
  }

  // set y in coordinate pair
  public void setY( int yValue )
  {
    y = yValue;  // no need for validation
  }

  // return y from coordinate pair
  public int getY()
  {
    return y;
  }

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

} // end class Circle