#!/usr/bin/perl

use strict;
use Tk;

my $haupt = new MainWindow;

my $links= $haupt->Frame();
$links->Label (-text => "Betrag in DM:")->pack();
my $dm = $links->Entry();
$dm->pack();

my $schalter = $links->Button (-text => "Berechnung", -command => \&abrechnung)->pack();
my $schalter2 = $links->Button (-text => "Beenden", -command=>[$haupt => 'destroy'])
                ->pack (-pady => "20");

my $rechts= $haupt ->Frame();
$rechts->Label (-text =>"Betrag in Euro:")->pack();
my $daten = $rechts -> Listbox();
$daten->pack();

$links ->pack (-side =>"left");
$rechts ->pack (-side =>"right");

MainLoop ();

sub berechnung {
        my $dm_sub = $dm ->get;
        my $euro = 0;
        
        $euro = $dm_sub / 1.95583;
        $daten->insert ('end', " ". $euro );
}

Tk::Error Undefined subroutine &main::abrechnung called at c:/perl/site/lib/Tk.
pm line 250.
Tk callback for .frame.button
Tk::_ANON_at c:/perl/site/lib/Tk.pm line 250
Tk::Button::butUp at c:/perl/site/lib/Tk/Button.pm line 175
<ButtonRelease-1>
<command bound to event>