#!/usr/bin/perl -w

use strict;
use warnings;
use diagnostics;

my %books;
my $someone;

$books{"fred"} =  3;
$books{"wilma"} = 1;
$books{"barney"} = 0;
$books{"pebbles"} = undef;

if ($books{$someone}) {
	print "$someone has at least one book checked out.\n";
	}