/* S0350.java
 *       中心極限定理 
 *         (C) H.Ishikawa 2008 
 */

package simulation;

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

public class S0350 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 = 640;
		int WIDTH = 640;
		int NUMBER = 5000;
		
		double P = 0.5; 	/* 確率p */
		int SIZE = 100; 	/* ヒストグラムの大きさ */
		int j; 				/* forのカウンタ */
		int i; 				/* forのカウンタ */
		int u; 				/* xをSIZE等分したものの整数部分 */
		int n = 1; 			/* n = 1, 2, 4, 8, 16 */
		double x; 			/* 一様乱数n個の合計 */
		double x1; 			/* 横軸 */
		double y1; 			/* 縦軸 */
		int f[] = new int[SIZE]; /* ヒストグラム */
		
		/* グラフィックの準備 */
		int hight = HIGHT / 5 - SPACE;
		w.setWindow(0, 0.0, 0.0, 16, 0.05,	SPACE, hight, WIDTH - SPACE, SPACE);
		w.axis(0, "", 1, "n=1", 0.01, g);
		w.setWindow(1, 0.0,	0.0, 16, 0.05, SPACE, 2 * hight, WIDTH - SPACE, hight + SPACE);
		w.axis(1, "", 1, "n=2", 0.01, g);
		w.setWindow(2, 0.0, 0.0, 16, 0.05, SPACE, 3 * hight, WIDTH - SPACE,	2 * hight + SPACE);
		w.axis(2, "", 1, "n=4", 0.01, g);
		w.setWindow(3, 0.0,	0.0, 16, 0.05, SPACE, 4 * hight, WIDTH - SPACE,	3 * hight + SPACE);
		w.axis(3, "", 1, "n=8", 0.01, g);
		w.setWindow(4, 0.0,	0.0, 16, 0.05, SPACE, 5 * hight, WIDTH - SPACE,	4 * hight + SPACE);
		w.axis(4, "", 1, "n=16", 0.01, g);
		g.setColor(Color.green);
		
		/* メイン */
		for (i = 0; i < 5; i++) {
			for (j = 1; j <= NUMBER; j++) {
				x = central(n);
				u = (int) (x * SIZE / n);
				f[u] = f[u] + 1;
			}
			/* ヒストグラムを書く */
			for (u = 0; u < SIZE; u++) {
				x1 = (double)u / SIZE * n;
				y1 = (double)f[u] / NUMBER;
				w.line(i, x1, 0, x1, y1, g);
				f[u] = 0;
			}
			n = n * 2;
		}
	}
	
	public double central(int n) {
		int k;
		double x = 0.0;
		for (k = 0; k < n; k++) {
			x = x + Math.random();
		}
		return (x);
	}
}