It's funny because this was actually pretty much my original answer, except that I didn't account for numbers less than zero.
The error message wasn't very helpful, so I found myself jumping through hoops trying to figure out how to handle floating point inaccuracies.

dude,It must be the best way to do this

Seemed like a simple task, but I broke my head solving it, 2 out of 3 conditions in the task were met and the last one was not accepted by me. Of course, I had to resort to help....... It turned out to be the same thing I wrote, just with some minor changes, which also turned out to be tricky, but now I see that it's even easier. I'm going to be a wreck today, work in 4 hours and I haven't slept.....

I knew there was a way to do this..

Your solution does the same you just take up another line to copy the contents of the initial string into a new one.

So that's how map works.

https://en.cppreference.com/w/cpp/numeric/math/sqrt

I have checked the following source: https://cplusplus.com/reference/cmath/sqrt/?kw=sqrt, and it did not say that std :: sqrt returns NaN when the argument is negative.
Could you please point out the source of your information? I will check that source if it is more reliable/updated.

agree.

Why is this answer getting so many best practice votes? Surely since sqrt returns a floating point value, with which arithmatic is limited in precision, which could cause false answers. It would also risk undefined behaviour due to integer overflow with larger n values as squaresquare (square_rootsquare_root) reaches the max value for an int.
Calculating square roots is also much slower than other integer operations so its not really an efficient approach. Am i mistaken here or missing something?

No need to check for negatives sqrt returns -NAN for negatives square it and it gives you NAN.

using namespace is in the script automatically and hes probably used to coding properly

there is "using namespace std;" at the beginning, so why did you add "std::" to abs function?

cool