use warnings;
use strict;

my $numbers = [ 1 .. 10 ];

print even($numbers);    ## call even number generator subroutine
print $/;

print odd($numbers);     ## call odd number generator subroutine
print $/;

## call combined even and odd number generator subroutine

my %even_n_odd_numbers = %{ even_odd($numbers) };
for ( keys %even_n_odd_numbers ) {
    print $_, " ", join " ", @{ $even_n_odd_numbers{$_} }, $/;
}

sub even {
    my ($numbers) = @_;
    my @even_numbers;

    for (@$numbers) {
        push @even_numbers, $_ if $_ % 2 == 0;
    }
    return @even_numbers if wantarray;
}

sub odd {
    my ($numbers) = @_;
    my @odd_numbers;

    for (@$numbers) {
        push @odd_numbers, $_ if $_ % 2 == 1;
    }
    return @odd_numbers if wantarray;
}

sub even_odd {
    my ($numbers) = @_;
    my %even_odd = ( 'even' => undef, 'odd' => undef, );

    for (@$numbers) {
        if ( $_ % 2 == 0 ) {
            push @{ $even_odd{'even'} }, $_;
        }
        else {
            push @{ $even_odd{'odd'} }, $_;
        }
    }
    return \%even_odd;
}