sub CLxsub
    {
    $x=0;
    $dis->delete('0.0','end');
    }
    sub xsysub
    {
    $x = $y;
    $y = $dis->get;
    $dis->delete('0.0','end');
    $dis->insert('end',$x);
    $res='s';
    }
    sub Rssub
    {
    my $aj=$dis->get;
    $dis->delete('0.0','end');
    $dis->insert('end',$y);
    $x=$y;
    $y=$z;
    $z=$t;
    $t=$aj;
    $res='s';
    }