CheckDigits::MBase_001(3pm) User Contributed Perl Documentation CheckDigits::MBase_001(3pm) NAME CheckDigits::MBase_001 - compute check digits for UPC (US) SYNOPSIS use Algorithm::CheckDigits; $rv = CheckDigits('upc'); if ($rv->is_valid('012345678905')) { # do something } $cn = $rv->complete('01234567890'); # $cn = '012345678905' $cd = $rv->checkdigit('012345678905'); # $cd = '5' $bn = $rv->basenumber('012345678905'); # $bn = '01234567890' DESCRIPTION ALGORITHM 1. Add all digits in odd-numbered positions. 2. Multiply the sum from step 1 with 3. 3. Add all digits in even-numbered positions. 4. Add the product from step 2 and the sum from step 3. 5. If the sum from step 4 is 0 modulo 10, the check digit is 0. Else the check digit is 10 minus the sum from step 4 taken modulo 10. METHODS is_valid($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> THANKS Aaron W. West pointed me to a fault in the computing of the check digit. SEE ALSO perl, CheckDigits, www.pruefziffernberechnung.de, www.export911.com/e911/coding/upcChar.htm, www.adams1.com/pub/russadam/upccode.html, http://www.upcdatabase.com. perl v5.10.0 2008-05-17 CheckDigits::MBase_001(3pm)