The Caesar Cipher, used by Julius Caesar around 58 BC, is a substitution cipher that shifts letters in a message to make it unreadable if intercepted. To decrypt, the receiver reverses the shift.
A shift number indicates how many letters the receiver should move along the alphabet to decrypt the message.
For example: encoded message of Khoor with a shift key of 3 would mean that the original
message had been shifted along the alphabet by 3 characters so reversing would lead to K -3 letters = H etc
leading to the decoded message of Hello
More reading on caesar cipher wikipedia link
Your mission is to create a decoder that will take in an encoded message and apply a shift key to return a decoded message
Decode the supplied encoded message whilst also providing tests to prove that the decoder works with positive and negative shifts, eg can shift +3 along the alphabet or -3 along the alphabet
The shift applies to the decoded message, so supplying the encoded message would mean your shift would be reversed!
encoded Khoor with a shift key of 3 means you'll have to go DOWN the alphabet 3...
Keep case sensitivity - capitals stay capitals and lowercase stays lowercase
Keep punctuation - punctuation doesn't get encoded, it stays the same and in place throughout
The mission continues - if time permits, the president of the world needs you to also create an encoder method
so messages can be provided with a shift key and a decoded message is produced! (remember
a shift towards an encoded message doesn't get reversed the same way decoding a message does!
Hello with 3 shift outputs to Khoor)
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- stackoverflow