Use of iterators over array indices

Question

I just wanted to know what is the main advantage of using the iterators over the array indices. I have googled but i am not getting the right answer.

Answer 1

As well as the points in other answers, iterators can also be faster (specifically compared to operator[]), since they are essentially iteration by pointer. If you do something like:

for (int i = 0; i < 10; ++i)
{
    my_vector[i].DoSomething();
}

Every iteration of the loop unnecessarily calculates my_vector.begin() + i. If you use iterators, incrementing the iterator means it's already pointing to the next element, so you don't need that extra calculation. It's a small thing, but can make a difference in tight loops.