import java.awt.*;
import java.applet.*;
import java.util.Random;

/**
 * This class draws random points in and around a circle.
 */
public class Monte4 extends Applet
{
	private static Random randy;
	private int NUM_POINTS;
	private int SIZE;
	
	private Image offScreenImage;
	private Graphics offScreenGraphics;

	private Label insideLabel;
	private TextField insideField;
	private Label outsideLabel;
	private TextField outsideField;
	
	private int randomInRange(int low, int high)
	{
		return (Math.abs(randy.nextInt()) % (high-low+1)) + low;
	}
	
	private double distance(int x1, int y1, int x2, int y2)
	{
		return Math.sqrt(Math.pow(x1-x2, 2) + Math.pow(y1-y2, 2));	
	}
	
	public void init()
	{
		randy = new Random();
		NUM_POINTS = Integer.parseInt(getParameter("points"));
		Dimension dim = getSize();
		SIZE = dim.width;
		
        setLayout(new BorderLayout());
		
	    Panel p = new Panel();
	    insideLabel = new Label("Inside:");
	    p.add(insideLabel);
	    insideField = new TextField(5);
	    p.add(insideField);
	    outsideLabel = new Label("Outside:");
	    p.add(outsideLabel);
	    outsideField = new TextField(5);
	    p.add(outsideField);
		
	    add(p, BorderLayout.SOUTH);
	}
	
    public void paint(Graphics g)
    {
		if (offScreenImage == null) {
			insideField.setText("0");
		    outsideField.setText("0");

            offScreenImage = createImage(SIZE, SIZE);
	        offScreenGraphics = offScreenImage.getGraphics();
			
	        offScreenGraphics.setColor(Color.red);
            g.setColor(Color.red);
	        offScreenGraphics.fillOval(0, 0, SIZE, SIZE);
            g.fillOval(0, 0, SIZE, SIZE);
            for (int i = 0; i < NUM_POINTS; i++) {
                int x = randomInRange(0, SIZE);
                int y = randomInRange(0, SIZE);
                if (distance(x, y, SIZE/2, SIZE/2) < SIZE/2) {
                    offScreenGraphics.setColor(Color.white);
                    g.setColor(Color.white);
					int value = Integer.parseInt(insideField.getText())+1;
				    insideField.setText(""+value);
                }
                else {
                    offScreenGraphics.setColor(Color.black);
                    g.setColor(Color.black);
					int value = Integer.parseInt(outsideField.getText())+1;
				    outsideField.setText(""+value);
                }
                offScreenGraphics.drawLine(x, y, x, y);
                g.drawLine(x, y, x, y);
            }
        }
        else {
            g.drawImage(offScreenImage, 0, 0, null);
        }
    }
}