13)

a) Write a java program RailFenceEncoder.java that reads in text from standard input and prints the characters in the odd positions, followed by the even positions. For example, if the original message is "Attack at Dawn", then you should print out "Atc tDwtaka an". This is a crude form of cryptography.

b) Write a program RailFenceDecoder.java that reads in a message encoded using the railfence transposition cipher and prints the original message by reversing the encryption process.