C++: Optimizing speed with vector/array?

Question

I have a nested for-loop structure and right now I am re-declaring the vector at the start of each iteration:

void function (n1,n2,bound,etc){

    for (int          


        

Answer 1

Well if you are really concerned about performance (and you know the size of n1 and n2 beforehand) but don't want to use a C-style array, std::array may be your friend.

EDIT: Given your edit, it seems an std::array isn't an appropriate substitute since while the vector size does not change each iteration, it still isn't known before compilation.