#!/usr/local/bin/perl

my $dups = &has_dup_letters (@ARGV);

if ($dups) {
  print "There is/are $dups dup(s).\n";
} else {
    print "There are no dups.\n";
}

sub has_dup_letters {

    # Takes a word and optionally an alphabet.
    # Returns the number of duplications (0 for none). eg abc
    # Returns the number of duplications are measured as letters removed to
    # make it unique. eg abbc == 1; abbbc == abbcc ==2;


    # Characters not in the alphabet are ignored regardless of
    # duplication.

    # If you do not supply an alphabet it will use a-z.  If you wanted
    # to check different characters (vowels) or numbers or punctuation,
    # just include them in your alphabet.

    # Case of A-Z is ignored. Trailing \n of words are chomped.

    my ($word, $alphabet) = @_;
    unless ($alphabet) {
      $alphabet = 'abcdefghijklmnopqrstuvwxyz'
    };
    $alphabet_size = length $alphabet;

    chomp $word;
    # down case it
    $word =~ tr/A-Z/a-z/;
    # Remove chars not in the alphabet.
    $word =~ s/[^$alphabet]//g;
    
    $alphabet =~ s/[$word]//g;
    unless ((length($alphabet) + length($word)) == $alphabet_size) {
        length ($alphabet) + length ($word) - $alphabet_size; # has dups
    } else {
        0; # No Dups
    }
}