Write an ISBN Validator in C language
What are ISBN?
ISBN, or International Standard Book Number, is a numeric
identifier for commercially printed books. Prior to 2007, they had
10 digits, but all newly issued ISBN use 13 digits. They are used
to uniquely identify a book and consist of several portions. These
include the registrant group, publisher, title, and a check digit.
The registrant group indicates where the publisher is located. For
example a registrant group of 0 or...