 CheckDigits::M10_005(3) compute check digits for Deutsche Post

## SYNOPSIS

use Algorithm::CheckDigits;
\$ic = CheckDigits('identcode_dp');
if (\$ic->is_valid('21.802 580.906 6')) {
# do something
}
\$cn = \$ic->complete('21.802 580.906');
# \$cn = '21.802 580.9066'
\$cd = \$ic->checkdigit('21.802 580.906 6');
# \$cd = '6'
\$bn = \$ic->basenumber('21.802 580.906 6');
# \$bn = '21.802 580.906'

## ALGORITHM

1.
Beginning left all numbers are weighted alternatively 4 and 9.
2.
3.
The sum of step 3 ist taken modulo 10.
4.
The check digit is the difference between 10 and the number from step 3.

## 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]>