---
name: "Algorithm::CheckDigits::M11_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::M11_004"
---

# Algorithm::CheckDigits::M11\_004(3pm)

compute check digits for CPF (BR), Titulo Eleitoral (BR)

## NAME

CheckDigits::M11\_004 - compute check digits for CPF (BR), Titulo Eleitoral (BR)

## SYNOPSIS

```
  use Algorithm::CheckDigits;
  $cpf = CheckDigits('cpf');
  if ($cpf->is_valid('043.033.407-90')) {
        # do something
  }
  $cn = $cpf->complete('043.033.407-');
  # $cn = '043.033.407-90'
  $cd = $cpf->checkdigit('043.033.407-90');
  # $cd = '90'
  $bn = $cpf->basenumber('043.033.407-90');
  # $bn = '043.033.407-'
```

## DESCRIPTION

### ALGORITHM

- 1\.

  From left to right all digits are multiplied with their position in the sequence.

- 2\.

  The sum of all products is computed.

- 3\.

  The sum of step 2 is taken modulo 11.

  a) If the result is 0 or 1 the checkdigit is 0

  b) otherwise the checkdigit is 11 minus the result.

- 4\.

  The first checkdigit is appended to the number and step 1 to 3 are repeated.

### 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*.