Simple code to validate and get scheme of credit card
The following algorithm can be used to check validity of a card number:
- Starting from the right, replace each second digit of the card number with its doubled value
- When doubling a digit produces a 2-digit number (e.g 6 produces 12), then add those 2 digits (1+2 = 3)
- Sum up all the digits
The card number is valid if the sum is divisible by 10
Example: Let's check if 5237 2516 2477 8133 is a valid credit card number.
- Double each second digit: 10 2 6 7 4 5 2 6 4 4 14 7 16 1 6 3
- Add 2-digit numbers: 1 2 6 7 4 5 2 6 4 4 5 7 7 1 6 3
- Sum up all the digits: 70
70 is divisible by 10, so 5237 2516 2477 8133 is a valid credit card number
Please implement a function that given a credit card number returns if it is valid
Card Scheme (Visa, MasterCard, JCB, etc) can be detected by the first digits of the card and the length of the card.
Example
| Scheme | Ranges | Number of Digits | Example number |
|---|---|---|---|
| American Express | 34,37 | 15 | 378282246310005 |
| JCB | 3528-3589 | 16-19 | 3530111333300000 |
| Maestro | 50, 56-58, 6 | 12-19 | 6759649826438453 |
| Visa | 4 | 13,16,19 | 4012888888881881 |
| MasterCard | 2221-2720, 51-55 | 16 | 5105105105105100 |