Multiplicative 2 should not be considered a magic number

[Ryan1729]

The 2 is considered a magic number in the following code.

func center(x, y, w, h int32) (cx int32, cy int32) {
	cx, cy = w/2+x, h/2+y

	return
}

In my opinion, whenever a number is divided by 2 or 2 and another number are multiplied together, then it is (almost?) always clear what is meant, and therefore it shouldn't be considered a magic number.

Trying to avoid it being considered a magic number with something like the following seems worse than leaving it as 2:

const havler = 2

func halve(x int32) (out int32) {
	out = x / havler

	return
}

That said, I think that something like this should still be counted as a magic number:

func foo(x int32) (y int32) {
    y = x + 2

    return 
}

(I'm using the named return value form, so that the examples actually produce error messages, given #11 is unresolved as I write this.)