Within the Usenet global discussion group system, freedom of expression is very important. However, it is also important that people should be able to avoid offensive postings if they so desire. The...

Within the Usenet global discussion group system, freedom of expression is very important. However, it is also important that people should be able to avoid offensive postings if they so desire. The solution is to encode potentially offensive text in a way that it looks like gibberish to the casual observer. However, the encoded text can be decoded easily by anyone who chooses.

The system used for the coding is called Rot-13. It works as follows. Each letter of the alphabet is replaced by the letter 13 places later in the alphabet, wrapping back to the beginning if necessary:

Create a single command that reads from a fi le named input, encodes the text using Rot-13, and writes the encoded text to standard output. Then create a command that reads encoded Rot-13 data and converts it back to ordinary text. Test your solutions by creating a text fi le named input, encoding it and then decoding i