#!/user/bin/perl

use warnings;
use strict;

my (@A, $A); # single, top level array of references

my (@B0, $B0); # mid level array of references for data set index_0
my (@B1, $B1); # mid level array of references for data set index_1

my (@Ct0, $Ct0); # low level array storing text for data set index_0
my (@Ct1, $Ct1); # low level array storing text for data set index_1

my %Ch0; # low level hash storing key-value pairs for data set index_0
my %Ch1; # low level hash storing key-value pairs for data set index_1

print "\nSAMPLE PROGRAM FOR PERLMONKS QUESTION\n";

$A[0] = \@B0; # array B0 contains references for data set index_0
$A[1] = \@B1; # array B1 contains references for data set index_1

$B0[0] = \@Ct0; # array Ct0 contains text data for data set index_0
$B1[0] = \@Ct1; # array Ct1 contains text data for data set index_1

$B0[1] = \%Ch0; # hash Ch0 has key-value pairs for data set index_0
$B1[1] = \%Ch1; # hash Ch1 has key-value pairs for data set index_1

&fetch_data(\@A);
&process_data(\@A);
&store_data(\@A); 

sub fetch_data
{
   # populating storage for data set index_0

   ${${${$_[0]}[0]}[0]}[0] = 10;
   ${${${$_[0]}[0]}[0]}[1] = 11;
   ${${${$_[0]}[0]}[0]}[2] = 12;

   ${${${$_[0]}[0]}[1]}{"dog"} = 15;
   ${${${$_[0]}[0]}[1]}{"cat"} = 16;
   ${${${$_[0]}[0]}[1]}{"bird"} = 17;

   # populating storage for data set index_1

   ${${${$_[0]}[1]}[0]}[0] = 20;
   ${${${$_[0]}[1]}[0]}[1] = 21;
   ${${${$_[0]}[1]}[0]}[2] = 22;

   ${${${$_[0]}[1]}[1]}{"dog"} = 25;
   ${${${$_[0]}[1]}[1]}{"cat"} = 26;
   ${${${$_[0]}[1]}[1]}{"bird"} = 27;
}

sub process_data
{
   # change two items in data set index_1 just to prove I can

   ${${${$_[0]}[1]}[0]}[2] = 24;
   ${${${$_[0]}[1]}[1]}{"bird"} = 29;
}

sub store_data
{
   # printing to screen is good "storage" for a sample program

   print "TEXT: $_[0]->[0][0][0]\n";
   print "TEXT: $_[0]->[0][0][1]\n";
   print "TEXT: $_[0]->[0][0][2]\n";
   print "\n";
   print "HASH: $_[0]->[0][1]{\"dog\"}\n";
   print "HASH: $_[0]->[0][1]{\"cat\"}\n";
   print "HASH: $_[0]->[0][1]{\"bird\"}\n";
   print "\n";
   print "TEXT: $_[0]->[1][0][0]\n";
   print "TEXT: $_[0]->[1][0][1]\n";
   print "TEXT: $_[0]->[1][0][2]\n";
   print "\n";
   print "HASH: $_[0]->[1][1]{\"dog\"}\n";
   print "HASH: $_[0]->[1][1]{\"cat\"}\n";
   print "HASH: $_[0]->[1][1]{\"bird\"}\n";
}