One way to handle an array of Buttons

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

/* One way to handle an array of buttons */

public class Buttons extends Applet implements ActionListener 
{
    //applet member data
    Button[] buttonArray;
    int nRows = 3;
    int nColumns = 4;
    int nTotalButtons = nRows * nColumns;

    public void init() 
    {
    	//declare a grid layout with no space between buttons
        setLayout(new GridLayout(nRows, nColumns, 0, 0));
        
        //declare a new array of buttons
        buttonArray = new Button[nTotalButtons];
        
        //initialize each of the buttons in the array
        //with an empty label
        for (int nNum = 0; nNum < nTotalButtons; nNum++) 
        {
            buttonArray[nNum] = new Button("");
            add(buttonArray[nNum]);
            buttonArray[nNum].addActionListener(this);
            buttonArray[nNum].setBackground(Color.yellow);
            //each button will send a message with its number
            buttonArray[nNum].setActionCommand("" + nNum);
        }
    }

    public void actionPerformed(ActionEvent e) 
    {
        //get the number of the button from getActionCommand
        //convert it to an int and store it in nButtonNumber
        int nButtonNumber = Integer.parseInt(e.getActionCommand());
        
        //display button Number at bottom of screen
         showStatus("Button number " + nButtonNumber);
         
         //change background of buttons
         if(buttonArray[nButtonNumber].getBackground() != Color.red)
         	buttonArray[nButtonNumber].setBackground(Color.red);
	 else
	     	buttonArray[nButtonNumber].setBackground(Color.blue);
    }
}