#!/usr/bin/perl

use warnings;
use strict;

package Box {

    sub new {
        my $classname = shift;
        my $self = {content => 1};
        return bless($self, $classname);
    }

    sub addContent {
        my $self = shift;
        my $addition = shift;
        $self->{content} += $addition;
    }

    sub showContent {
        my $self = shift;
        print $self->{content};
        print "\n";
    }
}

my $box = Box->new();
$box->addContent(5);
$box->showContent();