I'm studying different types of iterators right now. I've read that std::map has got bidirectional iterators. And std::set, std::list also have got this type of iterators. Why are they not random access iterators? Can anyone explain this to me? Thank you!
The Standard C++ library provides random access iterators to container types
for which access to an arbitrary element takes constant time, e.g. std::array,std::vector,
std::deque. That is because
a random access container is one of
which any element can be accessed in constant time.
std::list is not a random access container type:
access takes linear time. Neither is std::set: access
takes logarithmic time. Likewise std::map.