3 ms·
You don't really need a whole library to do it, just the first digit is enough. 3 = amex, 4 = visa, 5 = MC, 6 = discover.
by gergles 15y ago
You don't really need a whole library to do it, just the first digit is enough. 3 = amex, 4 = visa, 5 = MC, 6 = discover.