Re: Basic array question, need help

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

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    Date: Fri, 12 Dec 2003 02:21:47 GMT

    Thanks everyone for your help! I didn't realize I could instantiate the
    array in the constructor. Got it working now. Moving on to other
    problems... 

    -- 
-Kelly
kelly at farringtons dot net
Check out www.snittens.com
"Karl von Laudermann" <karl@ueidaq.com> wrote in message
news:e7e6125e.0312100843.1f8741bf@posting.google.com...
> "KellyH" <Kelly@whatever.com> wrote in message
news:<UqoBb.484596$Tr4.1330037@attbi_s03>...
>
> > 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.
>
> I assume by "load" you mean allocate and initialize. The correct place
> to do it is in the constructor, since that's exactly what constructors
> are for:
>
>    /** Creates a new instance of khNumberDisplayer */
>    public khNumberDisplayer()
>    {
>       // Allocate and initialize array
>       aNum = new int[50];
>       aNum[0]++;
>
>       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());
>    }
>
> The reason you can't access aNum from main is because main is a static
> method, which means it belongs to the khNumberDisplayer class in
> general, not any particular instance of it. Static methods cannot
> access non-static member variables, since static methods can be
> executed even when no instances of the class exist. If you really
> wanted to allocate the array from main rather than the constructor
> (though there's no good reason to), you could do it this way:
>
>     public static void main (String []args)
>     {
>         Frame NumberDisplayerWindow = new khNumberDisplayer();
>         NumberDisplayerWindow.setSize (700,300);
>         NumberDisplayerWindow.setBackground(Color.pink);
>         NumberDisplayerWindow.show();
>
>         // Call load_aNum on the instance
>         NumberDisplayerWindow.load_aNum();
>     }
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