If you don't want to copy the parameter (time and memory constraints), but want to use it without altering it, you pass it by const reference.

if you don't want to change number you shouldn't pass it as a reference

Because he is passing number as a reference.
This would mean if he would change number in the body of opposite, the value would be also manipulated outside the function.
This is clearly not wanted.
const declares that number will be treated as constant in this function and has two purposes:

• the caller knows that even though he is passing number as a reference, it will not be changed
• the programmer of opposite can not accidently change number as this would result into a compilation error.

Lol! Hilarious :)

So you allocate and initialize a vector and 4 strings just to throw them away in a moment, definitely not a best practice.

I love the simplicity. Taking notes.

Thanks for this solution. I'm studying it :)

I need to research your solution. Unfamiliar concepts, to me. Thanks!

LOL!

What's the benefit of making the function take a const int?

I only didn't because I've never heard of it, lol. Had I, I would've definitely mentioned it! :)

Amazing! I'm going to learn so much from your code. Thanks! Looks really clean.

Thanks for showing me how to use the ? conditional operator! You are amazing!

Finally! Using C++ I was stumped on how to return two string literals, lol. I was going to try a std::tuple, but that seemed like overkill, I guess.

Anyway, I finally got it! :)

Looking at the solutions, I found out how to return two different string literals.

Python test reference

https://www.codewars.com/docs/python-test-reference-1