#!/usr/bin/perl

my %hash = ("fred" => "flintstone", "dino" => undef, "barney" => "rubble", "betty" => "rubble");

my @ky = keys %hash;
my @vals = values %hash;

printf "%10s\t=>%10s\n", "keys", "values";
printf "%10s\t=>%10s\n" x @ky, @ky, @vals;


##</code><code>##

       keys           =>           values
    barney          =>             betty
       dino           =>              fred
    rubble           =>          rubble
                         =>      flintstone