C ++ language.
In a random test with data {{11, 69}, {62, 24}, {67, 30}, {68, 36}, {82, 31}}:
Expected: equal to [ 137.81, 79.8, 41.8, 38 ]
Actual: [ 137.8, 79.8, 41.8, 38 ].

But 689 / 5 = 137.80.

When transferring references to std::thread, I had to use std::ref.
Otherwise, a copy of the object was created in the thread.

1. Ok.
2. In this case, it is possible that the object will be transferred to another stream. If the object returns a link, then it will need to be wrapped in a pointer, etc.

Isn't a class constructor a function?

"Heavy version", which allows all of this return the way to shoot yourself in the foot. I delete this kata.

Not a function? What is this?

The problem is not solved.

Added test. Description changed.
Your solution does not pass this test. Sorry.

Changed the description of the kata. With multiple calls, the result can be cached.

Accepted your amendments.

Accepted your amendments.

C++: https://www.codewars.com/kumite/5e494ff8b95d28001ea8d0eb?sel=5e494ff8b95d28001ea8d0eb

Also added a C++ translation: https://www.codewars.com/kumite/5e491a2440d7a90032a6a484?sel=5e491a2440d7a90032a6a484
Please, take a look at it.

std::numeric_limits< char >::min() = -128.
std::numeric_limits< char >::max() = 127.

A char is regarded as an arithmetic type. Everything is correct.

Fixed. https://www.codewars.com/kumite/5e428093a962220014ddea0f?sel=5e43debb6f29fe001a6fa70b