# FreeBSD Manual Pages

```Algorithm::CheckDigitsUser0Contributed Perl Algorithm::CheckDigits::M10_005(3)

NAME
CheckDigits::M10_005 - compute check digits for Deutsche	Post
Identcode/Leitcode (DE)

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'

DESCRIPTION
ALGORITHM
1.  Beginning left all numbers are weighted alternatively 4 and 9.

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.

EXPORT
None by default.

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