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# NAME

CheckDigits::M43_001 - compute check digits for Code-39

# SYNOPSIS

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

\$c39 = CheckDigits('code_39');

if (\$c39->is_valid('AB-123K')) {
# do something
}

\$cn = \$c39->complete('AB-123');
# \$cn = 'AB-123K'

\$cd = \$c39->checkdigit('AB-123K');
# \$cd = 'K'

\$bn = \$c39->basenumber('AB-123K');
# \$bn = 'AB-123'
``````

# DESCRIPTION

## ALGORITHM

1. After replacing all non numeric letters with their respective values, the sum of all numbers is computers

2. The checkdigit is the sum from step 1 taken modulo 43.

## 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>`