Not a kata suggestion. Closing.

You can say that again!

Not a suggestion, this kata is not difficult if you think it through.

I've added the codegolf tag as per @hobovsky's suggestion though.

Also, rank may not be changed.

How does this require a "hack"?

As much as I despise code golf kata, I was quite surprised with amount of allowed solutions and possible ways of solving it.

But I agree that it would be nice to have codegolf tag.

thanks a lot. To tell the truth, I did not know the struct library before and I felt stupid reading the others' answers!

If you just do v = values, that is only passing the reference to it, not a copy of it. If you wanna clone it, there's other methods for it.