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Algorithm::CheckDigits::M11_013.3pm

NAME

CheckDigits::M11_013 - compute check digits for VAT Registration Number (GR)

SYNOPSIS

   use Algorithm::CheckDigits;
 
   $ustid = CheckDigits('ustid_gr');
 
   if ($ustid->is_valid('123456783')) {
         # do something
   }
 
   $cn = $ustid->complete('12345678');
   # $cn = '123456783'
 
   $cd = $ustid->checkdigit('123456783');
   # $cd = '3'
 
   $bn = $ustid->basenumber('123456783');
   # $bn = '12345678';
 
 

DESCRIPTION

ALGORITHM

1.

Beginning right with the digit before the checkdigit all digits are weighted with 2 ** position. I. e. the last digit is multiplied with 2, the next with 4, then 8 and so on.

2.

The weighted digits are added.

3.

The sum from step 2 is taken modulo 11.

4.

If the sum from step 3 is greater than 9, the check sum is 0 else it is the sum itself.

METHODS

is_valid($number)

Returns true only if $number consists solely of numbers and the rightmost 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 appended to the end of $number.

Returns the complete number with check digit or '' if $number does not consist solely of digits.

basenumber($number)

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

Return '' otherwise.

checkdigit($number)

Returns the check digits of $number if $number has valid check digits.

Return '' otherwise.

EXPORT

None by default.

AUTHOR

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

SEE ALSO

perl, CheckDigits, www.pruefziffernberechnung.de,