 CheckDigits::M97_001(3) compute check digits for VAT Registration Number (BE)

## SYNOPSIS

use Algorithm::CheckDigits;
\$ustid = CheckDigits('ustid_be');
if (\$ustid->is_valid('136695962')) {
# do something
}
\$cn = \$ustid->complete('1366959');
# \$cn = '136695962'
\$cd = \$ustid->checkdigit('136695962');
# \$cd = '62'
\$bn = \$ustid->basenumber('136695962');
# \$bn = '1366959'

## ALGORITHM

1.
The whole number (without checksum) is taken modulo 97.
2.
The checksum is difference of the remainder from step 1 to 97.

## 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 checkdigits of \$number if \$number has a valid check digit.

Return '' otherwise.

None by default.

## AUTHOR

Mathias Weidner, <[email protected]>