☆課題☆

import java.applet.Applet;
import java.awt.*;
public class rep6 extends Applet{
	int width;
	int height;
	Thre t[] = new Thre[10];
	public void init(){
		width=getSize().width;
		height=getSize().height;
	}
	public void start(){
		for(int i =0;i <10; i++){
			t[i] = new Thre(i);
			t[i].start();
		}
	}
	public void paint(Graphics g){
		g.setColor(Color.black);
		for(int i=0; i< 10; i++){
			g.fillOval(t[i].posx,t[i].posy,3,4);
			g.drawLine(t[i].sPlace, 0, t[i].posx, t[i].posy);
		}
	}

		class Thre extends Thread{
		int sPlace, shift = 10;
		int posx, posy;
		int i;
		public Thre(int i){
			sPlace = (int)(width * Math.random());
			this.i=i;
			
			posx = sPlace;
		}
			public void run(){
				Thread thre1=Thread.currentThread();
				while (t[i]== thre1) {
					repaint();
					posx += shift;
					if (posx >= width) {
						sPlace = (int)(width * Math.random());
						posx = sPlace;
						posy = 0;
					}
					posy += 20;
					if (posy >= height) {
						posy =0;
						sPlace = posx;
					}
				try{
					Thread.sleep(30);
				} catch (InterruptedException e) { }
			}
			}
		}
}