++ed by:

3 non-PAUSE users.

Mathias Weidner

# NAME

CheckDigits::M11_004 - compute check digits for CPF (BR), Título Eleitoral (BR)

# SYNOPSIS

``````  use Algorithm::CheckDigits;

\$cpf = CheckDigits('cpf');

if (\$cpf->is_valid('043.033.407-90')) {
# do something
}

\$cn = \$cpf->complete('043.033.407-');
# \$cn = '043.033.407-90'

\$cd = \$cpf->checkdigit('043.033.407-90');
# \$cd = '90'

\$bn = \$cpf->basenumber('043.033.407-90');
# \$bn = '043.033.407-'
``````

# DESCRIPTION

## ALGORITHM

1. From left to right all digits are multiplied with their position in the sequence.

3. The sum of step 2 is taken modulo 11.

a) If the result is 0 or 1 the checkdigit is 0

b) otherwise the checkdigit is 11 minus the result.

4. The first checkdigit is appended to the number and step 1 to 3 are repeated.

## 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, `<mamawe@cpan.org>`