NAME

       CheckDigits::M10_010 - compute check digits for Postscheckkonti (CH)

SYNOPSIS

         use Algorithm::CheckDigits;

         $pck = CheckDigits('postcheckkonti');

         if ($pck->is_valid('85-12345678-7')) {
               # do something
         }

         $cn = $pck->complete('85-12345678');
         # $cn = '85-12345678-7'

         $cd = $pck->checkdigit('85-12345678-7');
         # $cd = '7'

         $bn = $pck->basenumber('85-12345678-7');
         # $bn = '85-12345678'

DESCRIPTION

   ALGORITHM
       1.  The sequence of digits is processed left to right. For the first digit we assume a
           carry forward of 0.

       2.  For each digit d(i) the carry forward cf(i) is the digit at the the position p in the
           sequence ( 0, 9, 4, 6, 8, 2, 7, 1, 3, 5 ), where p is (d(i) + cf(i-1)) modulo 10.

       3.  The check digit is the difference of the sum from step 3 to the next multiple of 10.

   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, www.pruefziffernberechnung.de.