Printing an array to JLabel

Question

Let me preface this post by saying that I am a novice programmer. I realize my code my be subpar ..to say the least :)
I wrote a small practice program that when run, prints 5 sets of random numbers (ex. A3KRM-QP4S7-5GMBR-OY68B-Q8GBZ).
That part works fine on the command line, however I wanted to incorporate swing and display the output on a form. This is where I'm running into a problem. I'm trying to place output from a character array into a string and then print that to a label. The result is its printing a bunch of squares (ASCII?).
Here is where I'm creating my sets of random numbers, in the method "myGenerator()".
class keygen
//initialize random number generator
Random rand = new Random();
//initialize arrays          
char data[] = new char[36];
char key[] = new char[5];
//initialize integers and strings          
char keys[] = new char[30];
int a = 0, n = 35, q = 65, z = 48;
//CONSTRUCTOR
keygen()
//main method
public char[] myGenerator()      
//Populate charater array with numbers and letters
for (int x = 0; x <=25; x++)
data[x] = ((char)q);
q++;          
for(int x = 26; x <=35; x++)
data[x] = ((char)z);
z++;
//Print 5 groups of random characters
do
for (int b = 0;  b < 5; b++)
System.out.print(data[rand.nextInt(n+1)]);
f++;
System.out.print("-");
a++;
f++;
}     while (a < 4);
do
System.out.print(data[rand.nextInt(n+1)]);
a++;
f++;
}     while (a < 10);
return keys;
}Here is where I'm trying to add the output to the main form in a label (in the frmMain() constructor).
class frmMain extends JFrame
//add main menu bar to JFrame
private jmbMainMenu mmb;
private JFrame _mainFrame;
private JLabel mylabel = new JLabel();
void init()
setTitle("SandBox");
setJMenuBar(mmb = new jmbMainMenu() );
setSize (500,300);
setVisible(true);
addWindowListener(new WindowAdapter() {
public void windowClosing(WindowEvent e)
System.exit(0);
frmMain()
//Labels
setLayout(new FlowLayout(FlowLayout.CENTER, 50, 50));
String str1 = new String(new keygen().myGenerator());
mylabel.setText(str1);          
this.add(mylabel);
}My next step is to add a "Generate" button that displays a new random code when clicked, but I need to find out and understand what I'm doing wrong here first. Feel free to rip apart the code, and I'll appreciate any feedback.
Thanks!

Answer 1

I do have a main, I just didn't add it in my first post,
public class keyUtil
     public static void main (String[] args)
     new frmMain().init();
}I forgot to take out the "f" variable. I was using it earlier and forgot to remove it from the code. I can also see how my loop is confusing.
Mel,
Your absolutely right. Originally I tried doing something like this,
do
     for (int b = 0;  b < 5; b++)
          keys[f] = (data[rand.nextInt(n+1)]);
          f++;
          keys[f] = ("-");
          a++;
          f++;
}     while (a < 4);
do
          keys[f] = (data[rand.nextInt(n+1)]);
          a++;
          f++;
}     while (a < 10);
     return keys;Thats where the "f" came from. "f" was originally initialized to 0. I thought this would put a new character into each element of the "keys" array, but it didn't seem to work. I will go back and try this again.
Edited by: jd3cker on Jun 14, 2009 3:40 PM
Edited by: jd3cker on Jun 14, 2009 3:45 PM