---
name: "Algorithm::CheckDigits::MBase_003"
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::MBase_003"
---

# Algorithm::CheckDigits::MBase\_003(3pm)

compute check digits for SICI (Serial Item and Contribution Identifier)

## NAME

CheckDigits::MBase\_003 - compute check digits for SICI (Serial Item and Contribution Identifier)

## SYNOPSIS

```
  use Algorithm::CheckDigits;
  $sici = CheckDigits('sici');
  if ($sici->is_valid('0784-8679(20040308)6:<138>2.0.TX;2-H')) {
        # do something
  }
  $cn = $sici->complete('0784-8679(20040308)6:<138>2.0.TX;2-');
  # $cn = '0784-8679(20040308)6:<138>2.0.TX;2-H'
  $cd = $sici->checkdigit('0784-8679(20040308)6:<138>2.0.TX;2-H');
  # $cd = 'H'
  $bn = $sici->basenumber('0784-8679(20040308)6:<138>2.0.TX;2-H');
  # $bn = '0784-8679(20040308)6:<138>2.0.TX;2-';
```

## DESCRIPTION

### ALGORITHM

- 0

  In the string describing the number all letters (A-Z) are replaced with numbers 10-35 accordingly. All other non-numbers are replaced by 36.

- 1

  Beginning right the numbers at all odd positions are added.

- 2

  The sum from step 1 is multiplied by 3.

- 3

  Beginning right the numbers at all even positions are added.

- 4

  The sums from step 2 and 3 are added.

- 5

  The sum from step 4 is taken modulo 37.

- 6

  The checksum is 37 minus the sum from step 5 where numbers from 10 to 35 are represented by 'A' to 'Z' accordingly and 36 is represented by '#'.

### METHODS

- is\_valid($number)

  Returns true only if the last letter is a valid check letter according to the algorithm given above.

  Returns false otherwise,

- complete($number)

  The check letter for `$number` is computed and appended the end of `$number`.

  Returns the complete number with check letter or ''.

- basenumber($number)

  Returns the basenumber of `$number` if `$number` has a valid check digit.

  Return '' otherwise.

- checkdigit($number)

  Returns the check letter of `$number` if `$number` has valid check digits.

  Return '' otherwise.

### EXPORT

None by default.

## AUTHOR

Mathias Weidner, `"<mamawe@cpan.org>"`

## SEE ALSO

perl, CheckDigits, *www.pruefziffernberechnung.de*, *http://sunsite.berkeley.edu/SICI/sici.pdf*