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

```       CheckDigits::M11_003 - compute check digits for PKZ (GDR)

```

#### SYNOPSIS

```         use Algorithm::CheckDigits;

\$pkz = CheckDigits('pkz');

if (\$pkz->is_valid('150765400354')) {
# do something
}

\$cn = \$pkz->complete('15076540035');
# \$cn = '150765400354'

\$cd = \$pkz->checkdigit('150765400354');
# \$cd = '4'

\$bn = \$pkz->basenumber('150765400354');
# \$bn = '150765400354'

```

#### DESCRIPTION

```   ALGORITHM
1.  The checkdigit is set to 0.

2.  From right to left the digits are weighted (multiplied) with 2,4,8,5,10,9,7,3,6,1,2,4.

4.  The sum of step 3 is taken modulo 11.

5.  The value of step 4 is added to a multiple (0..9) of the weight of the checkdigit (2).

6.  The sum of step 5 is taken modulo 11.

7.  The checkdigit is the multiple of the weight of the checkdigit where the value of step
6 equals 10.

8.  If there can't be reached a value of 10 in step 6, the number cannot be taken as a
PKZ.

To validate a PKZ apply steps 2 to 4 to the complete number.

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.
```