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-'
  

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

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