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.