---
name: "Algorithm::CheckDigits::MXX_004"
section: "3pm"
platform: "linux"
package: "libalgorithm-checkdigits-perl"
version: "1.3.6-2"
release: "Debian 13 (Trixie)"
platforms: ["linux"]
url: "https://new.carta.tech/Algorithm::CheckDigits::MXX_004"
---

# Algorithm::CheckDigits::MXX\_004(3pm)

compute check digits for VAT RN (AT)

## NAME

CheckDigits::MXX\_004 - compute check digits for VAT RN (AT)

## SYNOPSIS

```
  use Algorithm::CheckDigits;
  $vat = CheckDigits('ustid_at');
  if ($vat->is_valid('U13585627')) {
        # do something
  }
  $cn = $vat->complete('U1358562');
  # $cn = 'U13585627'
  $cd = $vat->checkdigit('U13585627');
  # $cd = '7'
  $bn = $vat->basenumber('U13585627');
  # $bn = 'U1358562'
```

## DESCRIPTION

### ALGORITHM

- 1\.

  Beginning right all numbers before the check digit are weighted alternatively 1 and 2.

- 2\.

  The total of the digits of all products is computed and then subtracted from 96.

- 3\.

  The check digit is the sum of step 3 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, `"<mamawe@cpan.org>"`

## SEE ALSO

perl, CheckDigits, *www.pruefziffernberechnung.de*.