//RandomWalk.java
import java.awt.*;
import javax.swing.*;

public class RandomWalk extends JApplet {
    
    int lines;
    
    public void init() {
	String input;
	
	input = JOptionPane.showInputDialog("Enter # of steps to take");
	lines = Integer.parseInt(input);
    }
    
    public void paint( Graphics g ) {
	super.paint( g );

	int xPrev, yPrev, xNow, yNow;
	int xCenter=getWidth()/2;
	int yCenter=getHeight()/2;
	double totalDist=0, avgDist=0, dist;
	int scale=5;   //conversion to screen pixels

	xPrev = xNow = xCenter;   //start in center
	yPrev = yNow = yCenter;
	g.setColor(Color.RED);
	g.fillRect(xPrev-3,yPrev-3,5,5);
	g.setColor(Color.BLACK);       

	for (int i=1; i<=lines; i++) {
	    switch ((int)(Math.random()*4)) {
	    case 0:  //up
	    	yNow = yPrev - scale;
	    	break;
	    case 1:  //down
	    	yNow = yPrev + scale;
	    	break;
	    case 2:  //left
	    	xNow = xPrev - scale;
	    	break;
	    case 3:  //left
	    	xNow = xPrev + scale;
	    	break;
	    }

	    //draw line in red to see it as the leading edge. not visible...
	    //g.setColor(Color.RED);
	    //g.drawLine(xPrev,yPrev,xNow,yNow);
	    //redraw the line in black
	    //g.setColor(Color.BLACK);
	    g.drawLine(xPrev,yPrev,xNow,yNow);
	    
	    xPrev = xNow;
	    yPrev = yNow;
	    
	    int x = (xNow - xCenter) / scale;
	    int y = (yNow - yCenter) / scale;
	    dist = Math.sqrt(x*x+y*y);
	    totalDist += dist;
	    avgDist = totalDist / i;
	    
	    showStatus("Distance from origin: " + (int)dist + 
		       "   Average distance: " + (int)avgDist);

	}
    }
}
/*change scale for zoom
add ending point as blue rectangle
input scale factor from user
add Thread.sleep
input sleep value from user
*/