Fixed modulo 10 algorithm

This commit is contained in:
Dionysus 2024-05-12 04:01:54 -04:00
parent f3a54fc25c
commit 57c6f1439a
Signed by: acidvegas
GPG Key ID: EF4B922DB85DC9DE

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@ -1,41 +1,38 @@
#!/usr/bin/env python #!/usr/bin/env python
# Luhn Algorithm Example - Developed by acidvegas in Python (https://git.acid.vegas/msr90) # Luhn Algorithm Example - Developed by acidvegas in Python (https://git.acid.vegas/msr90)
def modulus10(card_number: str) -> str: def modulo10(card_number: str) -> str:
''' '''
Validate a card number using the Luhn Algorithm Validate a card number using the Luhn Algorithm
:param card_number: The card number to validate :param card_number: The card number to validate
''' '''
digits = [int(d) for d in card_number] digits = [int(d) for d in card_number]
total_sum = 0 total_sum = 0
reversed_digits = digits[::-1]
for i in range(len(reversed_digits)): for i, digit in enumerate(reversed(digits)):
digit = reversed_digits[i] if i % 2 == 0:
digit = digit * 2
if i % 2 != 0: if digit > 9:
digit = digit * 2 digit -= 9
if digit > 9: total_sum += digit
digit -= 9
total_sum += digit check_digit = (10 - total_sum % 10) % 10
full_card_number = card_number + str(check_digit)
check_digit = (10 - (total_sum % 10)) % 10 if (total_sum + check_digit) % 10 != 0:
full_card_number = card_number + str(check_digit) raise ValueError('failed luhn check (non-divisible by 10)')
if (total_sum + check_digit) % 10 != 0: return full_card_number
raise ValueError('failed luhn check (non-divisible by 10)')
return full_card_number
if __name__ == '__main__': if __name__ == '__main__':
card_number = input('Enter your card number without the last digit:') card_number = input('Enter your card number without the last digit: ')
if not card_number.isdigit(): if not card_number.isdigit():
raise ValueError('invalid card number') raise ValueError('invalid card number')
print(f'Full card number: {modulus10(card_number)}') print(f'Full card number: {modulo10(card_number)}')