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Assig 1. To ASCII or not to ASCII...

> We were told in the tutorial that the "Caesar Rot-13" was for alphabetic
> characters.  

Tsk tsk tsk, that's not really politically correct of you, showing a
very western-centric view of what an alphabet is ;-)

For the modern cryptanalist, and in the assignment text, Caesar's
encryption method is a cypher defined by the substitution equation:

        cyphertext_char = (plaintext_char + 13) MOD alphabet_size .
        
As such, it could have been used by Caesar, Sun Tzu, Alexander the Great,
Harun Al Rashid or your favourite general, in their favourite alphabet or
symbol set: Latin, Kanji, Greek, Arabic, ... Moreover, the assignment text is
rather clear:

        DESCRIPTION
        This program reads an ASCII text from file...

If the non-printable characters bother you, you can always filter the output
through od(1).

Ciao
Franco