#hash slice with a range
my %months;
@months{1..12} = qw/Jan Feb Mar Apr
                    May Jun Jul Aug
                    Sep Oct Nov Dec/;

##</code><code>##

sub get_days {
    my $month = shift;
    return 31 if grep { $month eq $_ } qw/1 3 5 7 8 10 12/;
    return 30 if grep { $month eq $_ } qw/4 6 9 11/;
    return 29 if $month eq '2';
    die "Bad month entered!\n";
}