import java.applet.Applet;
import java.awt.event.*;
import java.awt.*;
import java.util.*;
public class randoma extends Applet{
	TextField txt;
	Button b0;
	MyCanvas cnv;
	public void init() {
		setLayout(new BorderLayout());
		String s = getParameter("comment");
		if(s==null) s = "Good morning.";
		add("North", new Label(s));
		cnv= new MyCanvas(170, 200);
		add("Center", cnv);
		txt = new TextField("1000");   add("South", txt);
		b0 = new Button("again"); 
		b0.addActionListener(new myListener(this));
		add("West", b0);
	}
}
//JDK1.1.のevent model
class myListener implements ActionListener{
	randoma a;
	myListener(randoma a){
		this.a = a;}
	public void actionPerformed(ActionEvent e){
		a.cnv.set(Integer.parseInt(a.txt.getText()));
	}
}
class MyCanvas extends Canvas{
	int i, x, y, widthx, widthy, counter;
	Random r;
/*	public void MyCanvas(int widthx, int widthy) {  
 *      この宣言では、voidとして戻り値の型を宣言しているので 
 *      コンストラクタではなくメソッドになります.              */
	MyCanvas(int widthx, int widthy) {
		r = new Random();      // Randomクラスのインスタンス作成
		this.widthx = widthx;
		this.widthy = widthy;
		setSize(widthx, widthy); 
		setBackground(Color.white);
		setForeground(Color.darkGray);
	}
	void set(int counter){
		this.counter = counter;
		repaint();
	}          
	public void paint(Graphics g) {
		g.drawRect(0,0,widthx,widthy);
		for(i = 0; i < counter; i=i+1) { 
			x = (int)(widthx * (0.2 * r.nextGaussian() + 0.5));
			y = (int)(widthy * (0.2 * r.nextGaussian() + 0.5));
			g.fillOval(x,y, 3, 3);	
		}	
	}
}