What are the benefits of std::distance over subtracting iterators?
c++, iterator, std, stdvector
Solution
I would prefer `it - vec.begin()` precisely for the opposite reason given by Naveen: so it wouldn't compile if you change the vector into a list. If you do this during every iteration, you could easily end up turning an O(n) algorithm into an O(n^2) algorithm.
Another option, if you don't jump around in the container during iteration, would be to keep the index as a second loop counter.
Note: `it` is a common name for a container iterator,`std::container_type::iterator it;`.
Problem
I'm iterating over a vector and need the index the iterator is currently pointing at. What are the pros and cons of the following methods? - `it - vec.begin()` - `std::distance(vec.begin(), it)`