UPC
Uniform Product Code Check Digit

UPC is a FORTRAN90 library which can compute the check digit associated with a uniform product code (UPC), or it can report whether a 12-digit UPC is actually valid.

Licensing:

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

Languages:

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

Related Data and Programs:

ISBN, a FORTRAN90 library which can determine the check digit for an International Standard Book Number or report whether a given ISBN is valid.

LUHN, a FORTRAN90 program which computes the Luhn check digit for a string, and can validate a string.

Reference:

1. David Savir, George Laurer,
   The Characteristics and Decodability of the Universal Product Code,
   IBM Systems Journal,
   Volume 14, Number 1, pages 16-34, 1975.

Source Code:

• upc.f90, the source code.

Examples and Tests:

• upc_test.f90, a sample calling program.
• upc_test.txt, the output file.

List of Routines:

• 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.
• S_TO_DIGITS extracts N digits from a string.
• TIMESTAMP prints the current YMDHMS date as a time stamp.
• UPC_CHECK_DIGIT_CALCULATE returns the check digit of a UPC.
• UPC_IS_VALID reports whether a UPC is valid.

You can go up one level to the FORTRAN90 source codes.