/* S0420.java
 *        指数乱数の発生 
 *         (C) H.Ishikawa 2008 
 */

package simulation;

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

public class S0420 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 NUMBER  =    10000;
		int j;                     /* forのカウンタ */
		int u;                     /* τの整数部分 */
		int f[] = new int[100];   /* uの頻度 */
		double tau;                /* τ */
		double lambda = 1;         /* λ */
	
		
		/* グラフィックの準備 */
		int SPACE = 40;
		int HIGHT = 400;
		int WIDTH = 640;
  
		w.setWindow(0,  0.0,0.0,15,0.8,  SPACE,HIGHT-SPACE,WIDTH-SPACE,SPACE);
		w.axis(0, "tau", 1, "f[tau] / NUMBER", 0.1,g);
	

		/*メイン*/
		for (j = 0; j <= NUMBER; j++) {
			tau = -1.0 / lambda * Math.log(1.0 - Math.random());
			u = (int)tau;
		    f[u] = f[u] + 1;
		}
		
		/* ヒストグラムを書く */
		g.setColor(Color.red);
		for (u = 0; u < 15; u ++) {
			w.line(0, u + 0.5, 0, u + 0.5, (double)f[u] / NUMBER, g);
		}
	}
}