Basic array question, need help

From: KellyH (Kelly_at_whatever.com)
Date: 12/09/03 

Date: Tue, 09 Dec 2003 18:23:48 GMT

Hi, I hope someone can point me in the right direction.
I'll get it out of the way: Yes, I am a college student. No, I am not
looking for anyone to do my homework, just looking for help. I have been
reading this ng all semester, and found it very helpful. I just have a
stupid problem going on right now.

Here's the project:
We have to make a little frame with a text field, where the user inputs a
number, and a text area where a message is displayed. There are several
buttons on the frame: Enter, Average, Show Ascending, Show Descending,
Median, and High Number. We are to use an array to store up to 50 integers
the user enters.

Here's my problem:
My problem is that I can't figure out how to load the array. If I do it in
the Enter button event, then a new array is created each time an integer is
entered. I tested this by adding the current int to the int in the previous
cell. Oh, I am also storing the logical end of the array in the 0 cell. If
I try to load the array in the main, I get an error: Non-static method
load_aNum cannot be referenced from a static context. We had a project
previously where I used two arrays (pre-filled, not using input numbers),
and I loaded it in the main, and it worked fine. Don't know why this won't
work.

What I have so far (I've just been concentrating on getting the user numbers
to enter into the array. I'll worry about the rest of it later):

    import java.awt.*;
    import java.awt.event.*;
    import java.math.*;
    import java.util.Arrays.*; //thought I might need this later for sorting
the array

    public class khNumberDisplayer extends Frame implements ActionListener
    {

        private Button btnEnter, btnAvg, btnAscend, btnDescend, btnMedian,
btnHigh;
        private TextField tfNum1 = new TextField (5);

        private TextArea taMessage = new TextArea();

        private int[] aNum;
        private int lastSub =0;

    /** Creates a new instance of khNumberDisplayer */
    public khNumberDisplayer()
    {

     setTitle ("Number Displayer by Kelly");
     setLayout (new FlowLayout());
     add (new Label ("NUMBER "));
     add (tfNum1);

     add (new Label ("Message = "));
     add (taMessage);

     btnEnter = new Button ("Enter");
     add (btnEnter);
     btnEnter.addActionListener (new EnterHandler(this));
 addWindowListener(new CloseWindow());

    }

        public void load_aNum()
    {
         aNum = new int[50];
         aNum[0]++;
    }

        private static boolean isValid(int pInput)
    {
        boolean bResult;

        bResult = (pInput >=0) && (pInput<=9999);

        return bResult;
    }

    class EnterHandler implements ActionListener

    {
        khNumberDisplayer myFrame;
        EnterHandler (khNumberDisplayer pFrame)
        {
            myFrame=pFrame;
        }
        public void actionPerformed (ActionEvent event)
        {
            myFrame.EnterStuff();
            myFrame.repaint();
        }
    }

    public void EnterStuff()
    {
        String sMessage;
        boolean valid_test;
        int num1;

        num1 = Integer.parseInt(tfNum1.getText());

        //valid_test = (num1 >=1 && num1 <=200);
        if (isValid(num1))
        {

         aNum[aNum[0]] = num1;
         int total;
         total = aNum[aNum[0]] + aNum[aNum[0]-1];
         sMessage = "Number is valid. " + total;
        }
        else
          sMessage = "Number is not valid";

        taMessage.setText(sMessage);

   }

   public void actionPerformed(ActionEvent event)
    {
        repaint();
    }

    public static void main (String []args)
    {
        Frame NumberDisplayerWindow = new khNumberDisplayer();
        NumberDisplayerWindow.setSize (700,300);
        NumberDisplayerWindow.setBackground(Color.pink);
        NumberDisplayerWindow.show();
        load_aNum();
    }

    public class CloseWindow extends WindowAdapter
    {
        public void windowClosing (WindowEvent e)
        {
            System.exit(0);
        }
     }

   } 

-- 
-Kelly
kelly at farringtons dot net
Check out www.snittens.com