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

Why not something like that :

{
    vector< vector > vec(n1, vector(n2));

    for (int i=0; i

Edit: added scope braces ;-)