You are correct - that's an error in the specification, since it fails to state what you should do in such a case and is therefore incomplete. Well spotted :) You should indeed check that the Vigenère key meets the criteria for validity, and should print an error message and return 1 if it does not.

(Although there's only a very limited range of things you could do, without breaching some other portion of the specification. It would be incorrect for your cli function to ever call the Vigenère functions with arguments that breached the preconditions, so you mustn't do that. And the only way to avoid doing so is by validating the argument passed in cli.)

Cheers

Arran

Hi,

When we are validating the key input for the cli function, the spec only mentions that we must check if it is an appropriate int for Caesar encryption and decryption.

It does not state about checking if Vigenere is given an appropriate string where each of its characters are in the acceptable range, and is non-empty.

Is this implied or does cli not have to worry about this?

Thanks

Your question is already answered in the documentation for the Vigenère functions.

Cheers

Arran

ANONYMOUS wrote:

I also have a follow up question regarding the Vigenere cipher, if a character does not fall within the acceptable encrypting range and we have to copy it over, do we still advance in our progression along the key or do we not change our position until we use it?

For example, if HeLLO was to be encrypted and KEY is the key, would we do:

HeLLO KEYKE

or

HeLLO KKEYK

Thanks again

Yes, I understand these now, thanks again!