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

my %children;
#each parent has 3 children identified by their IDs
$children{'parent1'}{'a'}{'id'} = 'Child1P1';
$children{'parent1'}{'b'}{'id'} = 'Child2P1';
$children{'parent1'}{'c'}{'id'} = 'Child3P1';
$children{'parent2'}{'a'}{'id'} = 'Child1P2';
$children{'parent2'}{'b'}{'id'} = 'Child2P2';
$children{'parent2'}{'c'}{'id'} = 'Child3P2';


for my $parent (sort keys (%children)){
    print "The key value is a reference of type: ", ref $children{$parent}, $/;
    print "The parent is $parent:\n";
    for my $child (keys (%{$children{$parent}})){
           print "children of $parent-> $children{$parent}{$child}{'id'}\n";
           }
        print "\n\n";
    }

##</code><code>##

The key value is a reference of type: HASH
The parent is parent1:
children of parent1-> Child3P1
children of parent1-> Child1P1
children of parent1-> Child2P1


The key value is a reference of type: HASH
The parent is parent2:
children of parent2-> Child3P2
children of parent2-> Child1P2
children of parent2-> Child2P2


##</code><code>##