# OddEvenEncryption_v2.py
#
# Description: Write a program that encrypts and decrypts messages
#              using a transposition algorithm called "odd&even".
#
# Anne Lavergne
# Date: Feb. 2 2024

# Ask the user for a message to encrypt/decrypt
plainMsg = input("Please, enter a message to encrypt/decrypt: ")

# ***Encryption***

# Create two empty strings
strOfOddChars = ""
strOfEvenChars = ""

# Start with position (i.e., index) 0
index = 0

# Consider each character in the user's plain message
for char in plainMsg:
    
    # If index of character is odd
    if index % 2 == 1:

        # Put this character in strOfOddChars
        strOfOddChars = strOfOddChars + char # strOfOddChars =+ char
        
    else:
        # Otherwise put it in strOfEvenChars
        strOfEvenChars = strOfEvenChars + char # strOfEvenChars =+ char
    
    # Go to the next position (i.e., index) in user's plain message
    index = index + 1 # index += 1

# When finish, create the cipher
cipherMsg = strOfOddChars + strOfEvenChars

# Print the cipherMsg, i.e., the encrypted user message
print(f'''\nThe original plain message you entered was "{plainMsg}".
Once encrypted, your message looked like this "{cipherMsg}".''')