NAME

       CheckDigits::M07_001 - compute check digits modulo 7 method 1

SYNOPSIS

         use Algorithm::CheckDigits;

         $m001 = CheckDigits('m001');

         if ($m001->is_valid('1234567892')) {
               # do something
         }

         $cn = $m001->complete('123456789');    # $cn = '1234567892'

         $cd = $m001->checkdigit('1234567892'); # $cd = '2'

         $bn = $m001->basenumber('1234567892'); # $bn = '123456789'

DESCRIPTION

   ALGORITHM
       1.  All digits are added.

       2.  All digits at even positions are added.

       3.  The sum of step 1 and 2 is taken modulo 7.

       4.  This is the check digit.

   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 undef if $number does not consist
           solely of digits.

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

           Return undef otherwise.

       checkdigit($number)
           Returns the check digit belonging to $number or undef if $number does not consist
           solely of digits.

   EXPORT
       None by default.

AUTHOR

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

SEE ALSO

       perl, www.pruefziffernberechnung.de.