#!/usr/bin/perl
use strict;

my @animals = ( "bear<1>\n", "camel<0> <2>\n", "<2>horse\n", "duck<3>\n" );
my @changeTo = ( 'A', 'B', 'C', 'D' );
my @toFind = ( '<0>', '<1>', '<2>', '<3>' );

my $k = 0;
while($k < 5) {
	print map( change(\$_, \@toFind, \@changeTo) , @animals );
	my $t = shift(@changeTo);
	my $r = int(rand(100));
	push(@changeTo, $r);
	print "\n$k:\n" . "@changeTo" . "\n";;
	$k++;
}

sub change {
	my $str = shift;
	my $toFind = shift;
	my $changeTo = shift;
	my @f = @$toFind;
	my @c = @$changeTo;
	my $i = 0;
	foreach my $find (@f) {
		my $change = $c[$i];
		$$str =~ s/$find/$change/gi;
		$i++;
	}
	return $$str;
}