#! /usr/bin/perl -w
use strict;
use Devel::Size qw(total_size);

my %hash1 = (
    shave  => '',
    the    => '',
    modern => '',
    way    => '',
);

my %hash2 = (
    shave  => 1,
    the    => 1,
    modern => 1,
    way    => 1,
);

my %hash3 = (
    shave  => undef,
    the    => undef,
    modern => undef,
    way    => undef,
);

print "1: " . total_size(\%hash1) . "\n";
print "2: " . total_size(\%hash2) . "\n";
print "3: " . total_size(\%hash3) . "\n";
__END__
1: 309
2: 261
3: 245

##</code><code>##

my %hash;
undef(@hash{qw(shave the modern way)});