CheckDigits::M11_002(3) compute check digits for PZN (DE)

## SYNOPSIS

use Algorithm::CheckDigits;
\$pzn = CheckDigits('pzn');
if (\$pzn->is_valid('4877800')) {
# do something
}
\$cn = \$pzn->complete('487780');
# \$cn = '4877800'
\$cd = \$pzn->checkdigit('4877800');
# \$cd = '0'
\$bn = \$pzn->basenumber('4877800');
# \$bn = '487780'

## ALGORITHM

1.
From left to right beginning with the first position all digits are multiplied with 2,3,4,...
2.
3.
The checkdigit ist the sum of step 2 taken modulo 11.
4.
If the checkdigit is '10' the whole number is not taken as a PZN.

## 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.

None by default.

## AUTHOR

Mathias Weidner, <[email protected]>