Man pages sections > man3 > Algorithm::CheckDigits::M11_004

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

 CheckDigits::M11_004(3pm) User Contributed Perl Documentation CheckDigits::M11_004(3pm)

## NAME

CheckDigits::M11_004 - compute check digits for CPF (BR), Titulo 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.
2.
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.