The Java Program: MuApplet01.java
1 // MuApplet01.java -- Mu puzzle applet, version 1
2
3 /*
4 <applet code=MuApplet01.java width=300 height=300></applet>
5 */
6
7 import java.applet.Applet;
8 import java.awt.*;
9
10 class Derivation extends Canvas {
11
12 String derivation [] = new String [10];
13 int number = 0;
14
15 public void paint(Graphics g) {
16 g.setFont (new Font ("TimesRoman", Font.BOLD, 18));
17 for (int i=0; i<number; i++) {
18 g.drawString (i+" "+derivation[i], 40, 20+23*i);
19 }
20 }
21
22 }
23
24 public class MuApplet01 extends Applet {
25
26 TextField text;
27 Derivation d;
28
29 public void init() {
30 setLayout (new BorderLayout());
31 text = new TextField (10);
32 d = new Derivation ();
33 add ("North", text);
34 add ("Center", d);
35 setBackground (Color.white); // Make applet window stand out
36 d.derivation [d.number++] = "MI";
37 }
38
39 public boolean action (Event evt, Object arg) {
40 if (evt.target == text) {
41 String input = (String) arg;
42 d.derivation [d.number++] = input;
43 d.repaint();
44 return true;
45 } else {
46 return false;
47 }
48 }
49 }