Hi I was writing a code for a simple Caesar cipher decrypting program with python 3 and I got this error message when I was trying to run the program. Here's the code and I've got some description of the situation I'm having after the code.
def main():
def getInputFile():
"""get the name of the file user wants to decrypt and check
if its extension is txt or not and return the file name"""
filename = input('Enter the input file name: ')
while not filename.endswith('.txt'):
filename = input('Invalid file name extension. Please re-enter the input file name: ')
return filename
def decrypt(filename):
"""open the secret message and decrypt the caesar cipher and
return original message"""
readSecretMessage = open(filename, "r")
lines = readSecretMessage.readline()
cipher_key = int(lines[0])
secret_message = lines[1]
decrypted = ""
for letter in secret_message:
if letter in alphabet:
# decrypting
letter_index = (alphabet.find(letter) - cipher_key) % 26
decrypted = decrypted + alphabet[letter_index]
else:
decrypted = decrypted + letter
return decrypted
getInputFile()
message_decrypted = decrypt(filename)
print('The decrypted message is: ')
print(message_decrypted)
main()
And I get this error message from the fourth last line when I try to run the decrypt function. I thought it's all good since I returned 'filename' value from the getInputFile function but I guess not. Can someone help me figure out why this doesn't work and how should I fix this?
Thanks for your time!
Returning a variable called filename from the function does not automatically create a variable called filename in the scope that the function was called in. You need to explicitly assign the returned value to a variable:
f_name = getInputFile()
message_decrypted = decrypt(f_name)