/* S0620.java
 *        ２次元ランダムウォーク  
 *         (C) H.Ishikawa 2008 
 */

package simulation;

import java.applet.*;
import java.awt.*;
import java.awt.event.*;
import window.Window;


public class S0620 extends Applet implements ActionListener {
	Button button0;
	public void init() {
		button0 = new Button(" 再実行 ");
		add(button0);
		button0.addActionListener(this);
	}
	public void actionPerformed(ActionEvent e) {
		String label = e.getActionCommand();
		repaint();
	}

	public void paint(Graphics g) {
		Window w ;
		w = new Window();
		int        SPACE = 30;
		int        HIGHT = 400;
		int        WIDTH = 640;
		
		double     X_MAX =   80.0;
		double     Y_MAX =   50.0;
		
		double x,y;                       /* 粒子の座標 */
		double th;                        /* θ */
		int    t;						   /*時刻*/
		long T_END =   10000;             /* 終りの時刻 */
		
		/*グラフィックの準備*/
		w.setWindow(0,  -X_MAX, -Y_MAX, X_MAX, Y_MAX, SPACE,HIGHT-SPACE,WIDTH-SPACE,SPACE);
		w.axis(0, "", 10,"", 10, g);		
		w.moveTo(0, 0, 0, g);
  
		/*メイン*/
		x = 0.0;
		y = 0.0;
		for (t = 1; t <= T_END; t ++) {
			th = 2.0 * Math.PI * Math.random(); //(1)
		    x = x + Math.cos(th);               //(2)
		    y = y + Math.sin(th);               //(2)
		    g.setColor(Color.green);
		    w.lineTo(0, x, y, g);               //(3)
		}	
		stop();
	}
}