CheckDigits::M97_001 - compute check digits for VAT Registration Number (BE)

       Mathias Weidner, "<mamawe@cpan.org>"

ALGORITHM
       1.  The whole number (without checksum) is taken modulo 97.

       2.  The checksum is difference of the remainder from step 1 to 97.

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

           A leading 'BE' before the numbers will be ignored.

           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.

           A leading 'BE' before the digits is ignored for the computation and retained for the result.

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

           A leading 'BE' before the digits will be ignored and not returned with the result.

           Return '' otherwise.

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

           Return '' otherwise.

   EXPORT
       None by default.

       CheckDigits::M97_001 - compute check digits for VAT Registration Number (BE)

       perl,                         CheckDigits,                        <http://www.pruefziffernberechnung.de>.
       <https://en.wikipedia.org/wiki/VAT_identification_number>

perl v5.36.0                                       2022-10-13               Algorithm::CheckDigits::M97_001(3pm)

         use Algorithm::CheckDigits;

         $ustid = CheckDigits('ustid_be');

         if ($ustid->is_valid('136695962')) {
               # do something
         }

         $cn = $ustid->complete('1366959');
         # $cn = '136695962'

         $cd = $ustid->checkdigit('136695962');
         # $cd = '62'

         $bn = $ustid->basenumber('136695962');
         # $bn = '1366959'