Credit card authenticator is a program written in C to validate a credit card number. If the card is valid, the program checks if it is from Amex, MasterCard or Visa.
To check if the cards are valid and what type they are, the following methods were used:
-
The method used to validate the card number is the Luhn algorithm.
-
All American Express numbers start with 34 or 37; most MasterCard numbers start with 51, 52, 53, 54, or 55 and all Visa numbers start with 4
Compile the program
make creditRun using
./credit