/*
 *  ==================================================================
 *  Circle(): Implementation of the Circle class where data and circle
 *            properties can only be accessed through an interface.
 *
 *  Note. It is common programming practice to begin variable names
 *  with an underscore (e.g., _xxxx) when variables are either private  
 *  or protected.
 *
 *  Written by: Mark Austin                                April, 2009
 *  ==================================================================
 */

import java.lang.Math.*;

public class Circle {
    protected double _dX, _dY, _dRadius;

    // Constructor 

    public Circle () {}

    public Circle( double dX, double dY, double dRadius ) {
        _dX = dX;
        _dY = dY;
        _dRadius = dRadius;
    }

    // Compute the circle area ....

    private double Area() {
       return Math.PI*_dRadius*_dRadius;
    }

    // Create public interface for variables and area computation....

    public void setX (double dX) {
        _dX = dX;
    }

    public double getX () {
        return _dX;
    }

    public void setY (double dY) {
        _dY = dY;
    }

    public double getY () {
        return _dY;
    }

    public void setRadius (double dRadius ) {
        _dRadius = dRadius;
    }

    public double getRadius () {
        return _dRadius;
    }

    public double getArea() {
        return Area();
    }


    // Copy circle parameters to a string format ...

    public String toString() {
       return "(x,y) = (" + _dX + "," + _dY + "): Radius = " + _dRadius;
    }

    // Exercise methods in class Circle ...

    public static void main( String [] args ) {

       System.out.println("Exercise methods in class Circle");
       System.out.println("================================");

       Circle cA = new Circle();
       cA.setX(1.0);
       cA.setY(2.0);
       cA.setRadius(3.0);

       Circle cB = new Circle( 1.0, 2.0, 2.0 );

       System.out.printf("Circle cA : %s\n", cA.toString() );
       System.out.printf("Circle cA : Area = %5.2f\n", cA.getArea() );

       System.out.printf("Circle cB : %s\n", cB );
       System.out.printf("Circle cB : Area = %5.2f\n", cB.getArea() );
    }
}