• NAME
• SYNOPSIS
• ALGORITHM
• METHODS
• EXPORT
• AUTHOR
• SEE ALSO

NAME

CheckDigits::M11_017 - compute check digits for EC-No, EINECS, ELINCS

SYNOPSIS

  use Algorithm::CheckDigits;

  $ecno = CheckDigits('ecno');

  if ($ecno->is_valid('200-236-6')) {
        # do something
  }

  $cn = $ecno->complete('200-236-');
  # $cn = '200-236-6'

  $cd = $ecno->checkdigit('200-236-6');
  # $cd = '6'

  $bn = $ecno->basenumber('200-236-6');
  # $bn = '200-236-'

=head1 DESCRIPTION

ALGORITHM

1. From left to right all digits are multiplied with their position in the sequence.

2. The sum of all products is computed.

3. The sum of step 2 is taken modulo 11.

   The checkdigit is the last digit of the result.

METHODS

is_valid($number)

Returns true only if $number consists solely of numbers and the last digit is a valid check digit according to the algorithm given above.

Returns false otherwise,

complete($number)

The check digit for $number is computed and concatenated to the end of $number.

Returns the complete number with check digit or '' if $number does not consist solely of digits and spaces.

basenumber($number)

Returns the basenumber of $number if $number has a valid check digit.

Return '' otherwise.

checkdigit($number)

Returns the checkdigit of $number if $number has a valid check digit.

Return '' otherwise.

EXPORT

None by default.

AUTHOR

Mathias Weidner, <mathias@weidner.in-bad-schmiedeberg.de>

SEE ALSO

the perl manpage, the CheckDigits manpage, http://en.wikipedia.org/wiki/EC-No.