Provided by: libalgorithm-checkdigits-perl_0.50-1_all

#### NAME

```       CheckDigits::MXX_003 - compute check digits for DEM

```

#### SYNOPSIS

```         use Algorithm::CheckDigits;

\$dem = CheckDigits('dem');

if (\$dem->is_valid('GD0645027K1')) {
# do something
}

\$cn = \$dem->complete('GD0645027K');
# \$cn = 'GD0645027K1'

\$cd = \$dem->checkdigit('GD0645027K1');
# \$cd = '1'

\$bn = \$dem->basenumber('GD0645027K1');
# \$bn = 'GD0645027K'

```

#### DESCRIPTION

```   ALGORITHM
The algorithm is a variation of the Verhoeff scheme.

0   All letters are changed to numbers.

1   All digits are permutated according to a permutation table.

2   The permutated digits are combined using a dieeder table. The first with the second,
the result with the third, this result with the fourth and so on.

3   The result of the last combination in the dieeder table is in such a way combined that
the result is 0 (zero). The number used for this combination is the checksum.

For details look at the source.

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, <mathias@weidner.in-bad-schmiedeberg.de>

```

#### SEEALSO

```       perl, CheckDigits, www.pruefziffernberechnung.de,
```