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

I believe that vector iterators are implemented as pointers internally (in a good STL implementation), so in general there should be negligible performance difference between the two idioms. But if you want to know how these perform on your platform, why don't you measure it with a little test program? I don't think it would take more than 5 minutes to measure execution time of e.g. 1 million iterations with both variants...