#!/usr/bin/perl
use strict;
use warnings;

# initialize a hash
my %domains1 = ( com => 'commercial', edu => 'educational', org => 'non-profit' );

# use keys function in scalar context to get the number of keys
my $count = keys %domains1;
print "number of keys in hash: $count\n";

# use hash in boolean context -- should be TRUE here for not empty
if ( %domains1 )
{
  print "hash is not empty\n";
}
else
{
  print "hash is empty\n";
}

# zero out the hash
%domains1 = ();

# use keys function in scalar context to get the number of keys
$count = keys %domains1;
print "number of keys in hash: $count\n";

# use hash in boolean context -- should be FALSE here for empty
if ( %domains1 )
{
  print "hash is not empty\n";
}
else
{
  print "hash is empty\n";
}