#!/usr/bin/perl -w

use strict;

my @examples = ("one", "two", "three", "nine", "twenty",
                "one hundred and three", "one thousand",
                "one thousand two hundred",
                "eighth thousand seven hundred and fifty seven");

for my $cardinal (@examples) {
    my $ordinal = ordinalise($cardinal);
    print "$ordinal\n";
};

sub ordinalise {
    my $str = shift;
    my @arr = split " ", $str;
    my $word = pop @arr;
    my %ord = ("one" => "first",       "two" => "second",
               "three" => "third",     "four" => "fourth",
               "five" => "fifth",      "six" => "sixth",
               "seven" => "seventh",   "eight" => "eighth",
               "nine" => "ninth",      "ten" => "tenth",
               "eleven" => "eleventh", "twelve" => "twelfth");
    {
    $word =~ s/ty$/tieth/ and next;
    $word = $ord{$word} and next if defined $ord{$word};
    $word .= "th";
    }
    push @arr, $word;
    return join(" ", @arr);
};
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