Answer:
Explanation:
Using Python 3
def validate_card(card_number):
even_positioned_digits = card_number[::2]
odd_positioned_digits = card_number[1::2]
sum_even_digits = 0
for digit in even_positioned_digits:
if int(digit) * 2 > 9:
sum_even_digits += (int(digit) * 2) - 9
else:
sum_even_digits += int(digit)
sum_odd_digits = sum(int(x) for x in odd_positioned_digits)
total_sum = sum_even_digits + sum_odd_digits
return total_sum % 10 == 0
if __name__ == '__main__':
card_number = input('Enter a credit card number >>> ')
if validate_card(card_number):
print('The number is valid.')
else:
print('Invalid card number entered.')