ISBN
Check Digit for International Standard Book Number

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

Licensing:

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

Languages:

ISBN 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:

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.

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

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

Reference:

Source Code:

• isbn.c, the source code.
• isbn.h, the include file.

Examples and Tests:

• isbn_test.c, a sample calling program.
• isbn_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.
• I4_TO_ISBN converts an I4 to an ISBN digit.
• I4VEC_PRINT prints an I4VEC.
• ISBN_CHECK_DIGIT_CALCULATE determines the check digit for an ISBN.
• ISBN_IS_VALID reports whether an ISBN is valid.
• ISBN_TO_I4 converts an ISBN character into an integer.
• 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.