Algorithm::CheckDigits::MXX_002 (3pm)

  use Algorithm::CheckDigits;

  $cas = CheckDigits('cas');

  if ($cas->is_valid('1333-74-0')) {
        # do something
  }

  $cn = $cas->complete('1333-74-');
  # $cn = '1333-74-0'

  $cd = $cas->checkdigit('1333-74-0');
  # $cd = '0'

  $bn = $cas->basenumber('1333-74-0');
  # $bn = '1333-74-'

\s-1ALGORITHM\s0

1.

Beginning right with the second digit all digits are weighted ascending starting with 1.

2.

The sum of those products is computed.

3.

The checksum is the last digit of the sum from step 2 (modulo 10).

\s-1METHODS\s0

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.

\s-1EXPORT\s0

None by default.

Mathias Weidner, <[email protected]>

Aaron W. West pointed me to a fault in the computing of the check digit.

\s-1HERMIER\s0 Christophe made me aware that \s-1CAS\s0 is now assigning 10-digit \s-1CAS\s0 Registry Numbers (http://www.cas.org/newsevents/10digitrn.html)

perl, CheckDigits, www.pruefziffernberechnung.de, www.cas.org http://www.cas.org/expertise/cascontent/registry/checkdig.html