use strict;
use warnings;
sub printAll;

my %h=(a=>1, b=>2, c=>3);

my @aKeys = keys %h;
print "full set of keys: <@aKeys>\n";
print "print all key-value pairs:\n";
printAll(\%h) if (each %h);

# subroutine using while each loop
# possibly buried somewhere deep in a third party module
sub printAll {
  my $h=shift;
  while (my ($k, $v) = each(%$h)) {
    print "$k, $v\n";
  }
}

##</code><code>##

full set of keys: <c a b>
print all key-value pairs:
a, 1
b, 2

#whoops - no c, 3 printed out!!!