Can someone help me figure out what I\'m doing wrong? The program is supposed to

Question

Can someone help me figure out what I'm doing wrong?

The program is supposed to:

1. Accepts as input a text file named “card_data.txt” which contains several fictitious sixteen-digit credit card numbers as individual records,
validates each record as a sixteen-digit number for length,
2. uses Luhn’s Algorithm to determine if the number in each record is a valid sixteen-digit credit card number

Code

# Open file card_data.txt

file = open('card_data.txt', 'r')

# Read each line in file and strip

card_num = file.readline().strip()

card_num = int(card_num)

# Close the file

file.close()

# Check card length

def card_len():

index = 0

while card_num != '':

if card_num != 16:

print('This is not a valid card.')

else:

print('This card is a valid.')

index += 1

return card_num

# Check card_num follows alogrithim

def card_check():

length = len(card_num)

odd_sum = 0

even_sum = 0

if (length ==0):

return 0

else:

if(length % 2 == 0):

last = card_nun[-1]

even_sum += last

return even_sum + length

def main():

card_len()

card_check()

main()

Explanation / Answer

Everything is fine with the code, there are just type conversion mistakes at some places in your code. I have corrected them and commented the explanation. # Open file card_data.txt file = open('card_data.txt', 'r') # Read each line in file and strip card_num = file.readline().strip() card_num = int(card_num) # Close the file file.close() # Check card length def card_len(): index = 0 # card_num is int and you cannot compare it with string # so convert card_num to string by : str(card_num) while str(card_num) != '': # again card_num is int. And you cannot find the length of int directly # first convert the int to string and then find the length # as i have demonstrate : len(str(card_num)) if len(str(card_num)) != 16: print('This is not a valid card.') else: print('This card is a valid.') index += 1 return card_num # Check card_num follows alogrithim def card_check(): # again card_num is int. You cannot find the length of int directly # first convert int to string and then find its length length = len(str(card_num)) odd_sum = 0 even_sum = 0 if (length == 0): return 0 else: if (length % 2 == 0): # here you are trying to find the last digit of the card_num # but card_num is int. Andyou cannot find the last digit of int directly # first convert the int to string and then use [-1] operation to find last digit last = str(card_num)[-1] # now the 'last' stores the string value of last digit # So for adding last digit to even_sum convert last to int by : int(last) even_sum += int(last) return even_sum + length def main(): card_len() card_check() main()

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