import java.awt.*;
import java.applet.Applet;

// This applet uses polymorphism to decide which shape to draw. If shape is instantiated as a new
// Circle, it draws a circle, but if it is instantiated as a new Square, it draws a square.
public class Figures extends Applet
{
    private Shape shape; // shape is an instance variable whose type is an interface.
 
    public void paint (Graphics g)
    {
        shape = new Circle (Color.red, 100, 100);
        shape.drawShape (g);
        shape.drawAreaString (g);

        shape = new Square (Color.green, 100, 200);
        shape.drawShape (g);
        shape.drawAreaString (g);
    } // method paint
} // class Figures

// This interface defines the public methods in the classes that implement it.
interface Shape
{
    public void drawShape (Graphics g);
    public void drawAreaString (Graphics g);
} // interface Shape

class Circle implements Shape
{
    private Color color;
    private int x, y, diameter;

    Circle (Color c, int xPosition, int yPosition)
    {
        color = c;
        x = xPosition;
        y = yPosition;
        diameter = 50;
    } // constructor

    public void drawShape (Graphics g)
    {
        g.setColor (color);
        g.fillOval (x, y, diameter, diameter);
    } // method drawShape

    private int calculateArea ()
    {
        int area, radius = diameter / 2;
        area = (int)(Math.PI * radius * radius);
        return area;
    } // method calculateArea

    public void drawAreaString (Graphics g)
    {
        g.setColor (Color.black);
        int area = calculateArea ();
        g.drawString ("Area of Circle: "+ area, 100, 75);
    } // method drawAreaString
} // class Circle

class Square implements Shape
{
    private Color color;
    private int x, y, side;

    Square (Color c, int xPosition, int yPosition)
    {
        color = c;
        x = xPosition;
        y = yPosition;
        side = 50;
    } // constructor

    public void drawShape (Graphics g)
    {
        g.setColor (color);
        g.fillRect (x, y, side, side);
    } // method drawShape

    private int calculateArea ()
    {
        int area;
        area = side * side;
        return area;
    } // method calculateArea

    public void drawAreaString (Graphics g)
    {
        g.setColor (Color.black);
        int area = calculateArea ();
        g.drawString ("Area of Square: "+area, 100, 275);
    } // method drawAreaString
}// class Square