NAME

CheckDigits::M09_001 - compute check digits for Euro notes

SYNOPSIS

  use Algorithm::CheckDigits;
  $euro = CheckDigits('euronote');
  if ($euro->is_valid('X07738250357')) {
        # do something
  }
  $cn = $euro->complete('X0773825035');     # $cn = 'X07738250357'
  $cd = $euro->checkdigit('X07738250357'); # $cd = '7'
  $bn = $euro->basenumber('X07738250357'); # $bn = 'X0773825035'

DESCRIPTION

ALGORITHM

1.: Letters are replaced with their position in the alphabet ('A' = 1, ...).
2.: The total of the digits of all numbers is computed.
3.: This sum is taken modulo 9.
4.: The check digit is the difference between 8 and the number of step 3.

To validate the last digit of the total of the digits of all numbers inclusive check digit must be 8.

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 $number does not consist solely of digits.
basenumber($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>