NAME

       CheckDigits::M11_004 - compute check digits for CPF (BR), Titulo Eleitoral (BR)

SYNOPSIS

         use Algorithm::CheckDigits;

         $cpf = CheckDigits('cpf');

         if ($cpf->is_valid('043.033.407-90')) {
               # do something
         }

         $cn = $cpf->complete('043.033.407-');
         # $cn = '043.033.407-90'

         $cd = $cpf->checkdigit('043.033.407-90');
         # $cd = '90'

         $bn = $cpf->basenumber('043.033.407-90');
         # $bn = '043.033.407-'

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.

           a) If the result is 0 or 1 the checkdigit is 0

           b) otherwise the checkdigit is 11 minus the result.

       4.  The first checkdigit is appended to the number and step 1 to 3 are repeated.

   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.