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LUHN\ Luhn Check Digit for Error Detection {#luhn-luhn-check-digit-for-error-detection align=”center”} ====================================

LUHN is a C++ library which demonstrates the calculation and use of the Luhn check digit for error detection.

Licensing: {#licensing align=”center”}

The computer code and data files described and made available on this web page are distributed under the GNU LGPL license.

Languages: {#languages align=”center”}

LUHN is available in a C version and a C++ version and a FORTRAN90 version and a MATLAB version and a Python version.

BANK, a C++ library which can compute the check digit associated with a US Bank Routing Number check digit, or it can report whether a 9-digit code is actually valid.

ISBN, a C++ library which can determine the check digit for an International Standard Book Number or report whether a given ISBN is valid.

UPC, a C++ library which can determine the check digit for a Uniform Product Code (UPC) or report whether a given UPC is valid.

Source Code: {#source-code align=”center”}

luhn.cpp, the source code.
luhn.hpp, the include file.

Examples and Tests: {#examples-and-tests align=”center”}

luhn_prb.cpp, a sample calling program.
luhn_prb_output.txt, the output file.

List of Routines: {#list-of-routines align=”center”}

CH_IS_DIGIT is TRUE if a character is a decimal digit.
CH_TO_DIGIT returns the value of a base 10 digit.
I4VEC_PRINT prints an I4VEC.
LUHN_CHECK_DIGIT_CALCULATE determines the Luhn check digit of a string.
LUHN_CHECKSUM determines the Luhn checksum of a string.
LUHN_IS_VALID determines whether a string with Luhn check digit is valid.
S_DIGITS_COUNT counts the digits in a string.
S_TO_DIGITS extracts N digits from a string.
TIMESTAMP prints the current YMDHMS date as a time stamp.

You can go up one level to the C++ source codes.

Last revised on 11 September 2015.