# railfence.py - combined listings 3.2 and 3.3
# from Miller/Ranum text

def scramble2Encrypt(plainText):
    evenChars = ""
    oddChars = ""
    charCount = 0
    for ch in plainText:            
        if charCount % 2 == 0:          
            evenChars = evenChars + ch
        else:
            oddChars = oddChars + ch
        charCount = charCount + 1
    cipherText = oddChars + evenChars
    return cipherText
    
def scramble2Decrypt(cipherText):
    halfLength = len(cipherText) // 2
    oddChars = cipherText[:halfLength]
    evenChars = cipherText[halfLength:]
    plainText = ""
    
    for i in range(halfLength):
        plainText = plainText + evenChars[i]
        plainText = plainText + oddChars[i]
    
    if len(oddChars) < len(evenChars):
        plainText = plainText + evenChars[-1]

    return plainText

# aliases:
encrypt = scramble2Encrypt
decrypt = scramble2Decrypt