enigma.py

# (Run this code with Python 3 only.)
#
# This program decodes a secret message by advancing each
# letter by 2 places.  Spaces and punctuation should remain
# unchanged.

# Examples:
#   "nwrfml"     decodes into:    "python"
#   "ynnjc"      decodes into:    "apple"
#
# Notice how the encoded 'y' wraps back to 'a'.
#
# How would you rewrite this code to be more readable?
# ----------------------------------------------------

def decode(message):
  plain_message = ""
  for character in message:
    if ord(character) >= 97 and ord(character) <= (122):
      decoded_value = ord(character) + 2
      decoded_value = decoded_value if decoded_value <= 122 else (96 + decoded_value - 122)
      plain_message += chr(decoded_value)
    else:
      plain_message += character

  return plain_message


secret_message = "g fmnc wms bgbl'r rpylqjyrc gr zw fylb. \
rfyr'q ufyr amknsrcpq ypc dmp."

decoded_message = decode(secret_message)
print(decoded_message)