#!/usr/bin/perl

use strict;
use warnings;

use DateTime::Format::Strptime;

my $strp = DateTime::Format::Strptime->new(pattern => '%b %d %Y %I:%M%p');

my $string = 'Dec 11 2003 12:00AM';

my $dt = $strp->parse_datetime($string) or die;

$string = $dt->strftime('%m/%d/%Y'); # warning! illogical format!!

print "$string\n";