Caesar Cipher (P.163 Ex.7)

Specification

• Input:
  1. A word to encode.
  2. An integer as the key.
• Output: An encoded word.
• Relationship: ch is encoded as chr(ord(ch) + key)

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Get a word to encode.
Get a number as the key.
Each each character ch in the word, 
    output chr(ord(ch) + key).

Message - ABC
key - 3
DEF

Message - SBWKRQIRUILQDQFH
key - 23
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