$ampm = 'AM';
if ($hour >= 12)
{
    $hour -= 12;
    $ampm = 'PM';
}

##</code><code>##

$datetime = sprintf
   '%d:%02d:%02d %s, %s, %s %d, %d',
   $hour, $min, $sec, $ampm,
   $thisday, $thismon, $mday, $year + 1900;

##</code><code>##

$ampm = 'AM';
if ($hour >= 12)
{
    $hour -= 12;
    $ampm = 'PM';
}
$hour += 12 unless $hour;