CheckDigits::M10_010 − compute check digits for Postscheckkonti (CH)
use Algorithm::CheckDigits; $pck = CheckDigits('postcheckkonti'); if ($pck−>is_valid('85−12345678−7')) { # do something } $cn = $pck−>complete('85−12345678'); # $cn = '85−12345678−7' $cd = $pck−>checkdigit('85−12345678−7'); # $cd = '7' $bn = $pck−>basenumber('85−12345678−7'); # $bn = '85−12345678'
ALGORITHM
1. |
The sequence of digits is processed left to right. For the first digit we assume a carry forward of 0. |
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2. |
For each digit d(i) the carry forward cf(i) is the digit at the the position p in the sequence ( 0, 9, 4, 6, 8, 2, 7, 1, 3, 5 ), where p is (d(i) + cf(i−1)) modulo 10. |
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3. |
The check digit is the difference of the sum from step 3 to the next multiple of 10. |
METHODS
is_valid($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.
Mathias Weidner, <mathias AT weidner DOT in−bad−schmiedeberg.de>
perl, CheckDigits, www.pruefziffernberechnung.de.