# I need urgent help

i am very new to python language and i am asked to write the following code

write flowchart python code to implement the algorithm of mobile prepaid charging cards considering the following:

1. the system should generate charging numbers consisting of 14 numbers.
2. the generated number should contains the charging amount for example (10, 50, 100).
3. the system should give error messages if the number is fabricated, the number is already charged before or the charging data is expired.

What code do you have so far? What do you need help with?

``````chargingcardPrefixList = [
['5', '0'], ['5', '0'], ['5', '0'], ['1', '0'], ['1', '0', '0']]

def completed_number(prefix, length):
"""
'prefix' is the start of the CC number as a string, any number of digits.
'length' is the length of the CC number to generate. Typically 13 or 16
"""

ccnumber = prefix

# generate digits

while len(ccnumber) < (length - 1):
digit = str(generator.choice(range(0, 10)))
ccnumber.append(digit)

# Calculate sum

sum = 0
pos = 0

reversedCCnumber = []
reversedCCnumber.extend(ccnumber)
reversedCCnumber.reverse()

while pos < length - 1:

odd = int(reversedCCnumber[pos]) * 2
if odd > 9:
odd -= 9

sum += odd

if pos != (length - 2):

sum += int(reversedCCnumber[pos + 1])

pos += 2

# Calculate check digit

checkdigit = ((sum / 10 + 1) * 10 - sum) % 10

ccnumber.append(str(checkdigit))

return ''.join(ccnumber)

def charging_card_number(rnd, prefixList, length, howMany):

result = []

while len(result) < howMany:

ccnumber = copy.copy(rnd.choice(prefixList))
result.append(completed_number(ccnumber, length))

return result

def output(title, numbers):

result = []
result.append(title)
result.append('-' * len(title))
result.append('\n'.join(numbers))
result.append('')

return '\n'.join(result)

#
# Main
#

generator = Random()
generator.seed()        # Seed from current time

charging_card = credit_card_number(generator, chargingcardPrefixList, 14, 10)
print(output("charging_card_numb", charging_card))
``````

here:

``````generator = Random()
``````

Random isn’t defined anywhere.

i only need the code that checks the validity of card numbers

but that is an existing algorithm named Luhn Algorithm, no need to re-invent the wheel

ok great can you help me in allying this algorithm to my code above

but the code you posted above doesn’t even work.

with a simple google search we can just find the algorithm:

https://stackoverflow.com/questions/21079439/implementation-of-luhn-formula