Thoughts...

[geekborg]

While I praise your urge to help the community, I don't think you should pursue both is-even and is-odd projects, because, from a developper's point of view, they are utterly nonsense. There exist some trivial bitwise computations which do this in a couple of CPU instructions:
isEven(a) -> (a & 1) == 0
isOdd(a) -> (a & 1) == 1
You need to take a little step-back, and re-think carefully about the real usefulness of these projects. Plus, you should not make publicly visible a code which encourages bad practices; and trying to brute-force a trivial parity test with a huge if-else block is definitely a bad practice.
Please, consider that I am actually trying to help you; I promise you, at some point, when you will look back at these projects, you will wish to never have thought conducting a parity test that way.
Respectfully.