use Tk;
use strict;

my $init = 0;
my $display = 1;

my $mw = MainWindow->new;
$mw->geometry("300x100");

my $menubar = $mw->Frame()->pack(-side => 'left');

my $mainframe = $mw->Frame(-bg => 'darkblue', -container => 0);
$mainframe->pack(-fill => 'both', -side => 'top', -expand => 1);

$menubar->Button(-text => "Start", -command => \&start)->pack(-side => "left");
$menubar->Button(-text => "Stop", -command => \&stop)->pack(-side => "left");
$menubar->Button(-text => "Reset", -command => \&reset)->pack(-side => "left");

my $abc = $mainframe->Label(-textvariable => \$display);
$abc->pack;
$abc->repeat($display, \&update);

MainLoop;

sub start {
$init=1;
}

sub stop {
$init=0;
}

sub reset {
$init=0;
$display=0;
}

sub update {
if ($init==1){
$display++;
}
}