Java Code

/* Demonstrate loops with animation
 * @author: E.S.Boese
 * @version : Fall 2005
 */
import java.awt.*;
import javax.swing.*;
public class AnimateThreads extends JApplet implements
Runnable
{
   
    int x, y, size, move, speed, count;
    Thread thread;
    public void init( )
    {
   
        x = 0;
        y = 50;
        size = 20;	// width and height same
        move = 2; //num pixels to move each time thru loop
        count = 0;
        thread = new Thread(this);
		thread.start( );
    }
    public void run( )
    {
   
			try
			{
   
				while( true )
				{
   
				    repaint( );
				    thread.sleep( 50 );
			     // slow down painting so we can see it
				}
			}catch( Exception e )
			{
   
			}
    }
    public void paint ( Graphics g )
    {
            g.clearRect ( 0,0,300,300);  // erase space
            
			x = x + move;   // new x coodinate, y stays same
            g.fillRect ( x, y, size, size ); 
                                 // did we hit the edge
                                 // of the applet?
            if ( x + size > getWidth( ) )  
                move = -move;	// if so, go back
            if ( x < 0 )
				move = -move;
     }
}