The program that shows whether the entered credit card number is valid and if valid which bank it belongs to.
Luhn Algorithm is used for card number validation process. In this program, Luhn's Algorithm is written in C language.
Credit card numbers are classified as follows:
Amerikan Express -> number of digits:15 first two digits: 34 or 37
VISA -> number of digits: 13 or 16 first two digits: 4
MASTERCARD -> number of digits: 16 first two digits: 51,52,53,54 or 55
The program is written according to only these values.
Here, online card number validator site and it contains more information about Luhn Algorithm: https://www.datageneratortools.com/card/validator
For more information about Anatomy of a Credit Card: https://www.creditcardinsider.com/learn/anatomy-of-a-credit-card/