[c++] Return a 2d array from a function

What you are (trying to do)/doing in your snippet is to return a local variable from the function, which is not at all recommended - nor is it allowed according to the standard.

If you'd like to create a int[6][6] from your function you'll either have to allocate memory for it on the free-store (ie. using new T/malloc or similar function), or pass in an already allocated piece of memory to MakeGridOfCounts.