Speed accessing a std::vector by iterator vs by operator[]/index?

Question

Say, I have a

std::vector v;

in my code and I need to access its elements very often in the program, looping them forwa

Answer 1

A simple loop-based benchmark has been fulfilled. I used VS 2010 SP1 (release configuration).

1. Use iterators (*it = *it + 1;)
2. Use indices (vs[i] = vs[i] + 1;)

In several billions of iterations the second approach turned out to be a bit faster, by 1%. The result (indices are slightly faster than iterators) is reproducible but the difference, as I said, is very small.