---
name: "Algorithm::CheckDigits::M07_001"
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::M07_001"
---

# Algorithm::CheckDigits::M07\_001(3pm)

compute check digits modulo 7 method 1

## 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, `"<mamawe@cpan.org>"`

## SEE ALSO

perl, *www.pruefziffernberechnung.de*.