Testing to see if a button has been pushed for a second time

Question

I am writing a calculator. and i need to know how to test if a button has already been pushed. here is my code:
*Old School Calculator
*@Collin Doering
*Version 2.00
import java.awt.*;
import javax.swing.*;
import java.awt.event.*;
public class OSC implements ActionListener {
     private JButton b1, b2, b3, b4, b5, b6, b7, b8, b9, b0, bp, badd, bsub, be;
     private JTextField numbox;
     private int fnum = 0;
     private int snum = 0;
     final static String LOOKANDFEEL = null;
     public Component createComponents() {
          b1 = new JButton("1");
          b1.addActionListener(this);
          b2 = new JButton("2");
          b2.addActionListener(this);
          b3 = new JButton("3");
          b3.addActionListener(this);
          b4 = new JButton("4");
          b4.addActionListener(this);
          b5 = new JButton("5");
          b5.addActionListener(this);
          b6 = new JButton("6");
          b6.addActionListener(this);
          b7 = new JButton("7");
          b7.addActionListener(this);
          b8 = new JButton("8");
          b8.addActionListener(this);
          b9 = new JButton("9");
          b9.addActionListener(this);
          b0 = new JButton("0");
          b0.addActionListener(this);
          bp = new JButton(".");
          bp.addActionListener(this);
          badd = new JButton("+");
          badd.addActionListener(this);
          bsub = new JButton("-");
          bsub.addActionListener(this);
          be = new JButton("=");
          be.addActionListener(this);
          numbox  = new JTextField( 5 ) ;
        numbox.setText( "" );
        numbox.setEditable( false );
        numbox.setBackground( Color.white );
        numbox.setHorizontalAlignment( JTextField.CENTER );
          JPanel pane = new JPanel(new GridLayout(4, 4));
        pane.add(numbox);
        pane.add(b1);
        pane.add(b2);
        pane.add(b3);
        pane.add(badd);
        pane.add(b4);
        pane.add(b5);
        pane.add(b6);
        pane.add(bsub);
        pane.add(b7);
        pane.add(b8);
        pane.add(b9);
        pane.add(be);
        pane.add(b0);
        pane.add(bp);
        pane.setBorder(BorderFactory.createEmptyBorder(
                                        30, //top
                                        30, //left
                                        10, //bottom
                                        30) //right
        return pane;
     public void actionPerformed(ActionEvent e) {
          if (e.getSource() == b1) {
               fnum = 1;
               numbox.setText("1");
               if (e.getSource() == b1) {
                    fnum = 11;
                    numbox.setText("11");
               if (e.getSource() == b2) {
                    fnum = 12;
                    numbox.setText("12");
          if (e.getSource() == b2) {
               fnum = 2;
               numbox.setText("2");
          if (e.getSource() == b3) {
               fnum = 3;
               numbox.setText("3");
          if (e.getSource() == b4) {
               fnum = 4;
               numbox.setText("4");
          if (e.getSource() == b5) {
               fnum = 5;
               numbox.setText("5");
          if (e.getSource() == b6) {
               fnum = 6;
               numbox.setText("6");
          if (e.getSource() == b7) {
               fnum = 7;
               numbox.setText("7");
          if (e.getSource() == b8) {
               fnum = 8;
               numbox.setText("8");
          if (e.getSource() == b9) {
               fnum = 9;
               numbox.setText("9");
          if (e.getSource() == b0) {
               fnum = 0;
               numbox.setText("0");
          if (e.getSource() == bp) {
               fnum = 0;
               numbox.setText("0.");
          if (e.getSource() == badd) {
               fnum = 0;
               numbox.setText("N/A");
          if (e.getSource() == bsub) {
               fnum = 0;
               numbox.setText("N/A");
          if (e.getSource() == be) {
               fnum = 0;
               numbox.setText("N/A");
     private static void initLookAndFeel() {
        String lookAndFeel = null;
        if (LOOKANDFEEL != null) {
            if (LOOKANDFEEL.equals("Metal")) {
                lookAndFeel = UIManager.getCrossPlatformLookAndFeelClassName();
            } else if (LOOKANDFEEL.equals("System")) {
                lookAndFeel = UIManager.getSystemLookAndFeelClassName();
            } else if (LOOKANDFEEL.equals("Motif")) {
                lookAndFeel = "com.sun.java.swing.plaf.motif.MotifLookAndFeel";
            } else if (LOOKANDFEEL.equals("GTK+")) { //new in 1.4.2
                lookAndFeel = "com.sun.java.swing.plaf.gtk.GTKLookAndFeel";
            } else {
                System.err.println("Unexpected value of LOOKANDFEEL specified: "
                                   + LOOKANDFEEL);
                lookAndFeel = UIManager.getCrossPlatformLookAndFeelClassName();
            try {
                UIManager.setLookAndFeel(lookAndFeel);
            } catch (ClassNotFoundException e) {
                System.err.println("Couldn't find class for specified look and feel:"
                                   + lookAndFeel);
                System.err.println("Did you include the L&F library in the class path?");
                System.err.println("Using the default look and feel.");
            } catch (UnsupportedLookAndFeelException e) {
                System.err.println("Can't use the specified look and feel ("
                                   + lookAndFeel
                                   + ") on this platform.");
                System.err.println("Using the default look and feel.");
            } catch (Exception e) {
                System.err.println("Couldn't get specified look and feel ("
                                   + lookAndFeel
                                   + "), for some reason.");
                System.err.println("Using the default look and feel.");
                e.printStackTrace();
    private static void createAndShowGUI() {
        initLookAndFeel();
        JFrame.setDefaultLookAndFeelDecorated(true);
        JFrame frame = new JFrame("SwingApplication");
        frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
        OSC app = new OSC();
        Component contents = app.createComponents();
        frame.getContentPane().add(contents, BorderLayout.CENTER);
        frame.pack();
        frame.setVisible(true);
    public static void main(String[] args) {
        javax.swing.SwingUtilities.invokeLater(new Runnable() {
            public void run() {
                createAndShowGUI();
}then when i push my button 1 it outputs 11. I know why but what i am trying to do is when 1 is pushed once the variable fnum = 1; but what is hapening is when the button is pushed once it outputs 11 because i don't know. Could some one please help me :) thanx.

Answer 1

I am writing a calculator. and i need to know how to test if a button has already been pushed. here is my code:I don't know why you care if a button has been pressed more than once.
IT IS NOT A SCHOOL PROJECT I AM IN IN NO PROGRAMMING CLASS UNTIL
NEXT YEAR!! I do talk to the programmin gteacher at my school often i am
doing gr.12 work. i am in gr.9. so could you help me. the programming teacher
(Mr.Philino) hurt his back so he won't be in and i can't do anything until i find
this out. THANX!! Obviously you are not yet mature enough to be doing grade 12 work and frankly, I'm getting tired of your attitude. We don't care what grade you are in or what has happened to your teacher. We are not here to babysit you. So grow up act like an adult and maybe people will continue to help. Changing your userid would be a good start so people don't know who you are.
Here is one last attempt at helping:
import java.awt.*;
import java.awt.event.*;
import javax.swing.*;
public class ButtonCalculator extends JFrame implements ActionListener
     private JButton[] buttons;
     private JTextField display;
     public ButtonCalculator()
          display = new JTextField();
          display.setEditable( false );
          display.setHorizontalAlignment(JTextField.RIGHT);
          JPanel buttonPanel = new JPanel();
          buttonPanel.setLayout( new GridLayout(0, 5) );
          buttons = new JButton[10];
          for (int i = 0; i < buttons.length; i++)
               String text = String.valueOf(i);
               JButton button = new JButton( text );
               button.addActionListener( this );
               button.setMnemonic( text.charAt(0) );
               buttons[i] = button;
               buttonPanel.add( button );
          getContentPane().add(display, BorderLayout.NORTH);
          getContentPane().add(buttonPanel, BorderLayout.SOUTH);
          setResizable( false );
     public void actionPerformed(ActionEvent e)
          JButton source = (JButton)e.getSource();
          display.replaceSelection( source.getActionCommand() );
     public static void main(String[] args)
          ButtonCalculator frame = new ButtonCalculator();
          frame.setDefaultCloseOperation( EXIT_ON_CLOSE );
          frame.pack();
          frame.setLocationRelativeTo( null );
          frame.setVisible(true);
}