/**
 * A circular shape knows its own radius and how to compute its area.
 * @author Dung X. Nguyen
 * @Copyright 2002 by Dung X. Nguyen - All rights reserved.
 */
public class Circle implements IShape {
    /**
     * The radius of the circle.
     */
    private double _radius;

    /**
     * Initializes this Circle with a given radius.
     * @param radius the radius, >= 0.
     */
    public Circle(double radius) {
        _radius = radius;
    }

    /**
     * Pie are square!
     * @return this Circle's area.
     */
    public double getArea() {
        return Math.PI * _radius * _radius;
    }

    /**
     * Overrides the inherited method from class Object.
     * @return a String describing a Circle and its radius.
     */
    public String toString() {
        return "Circle(radius = " + _radius + ")";
    }
}