The C++ Standard Library: A Tutorial and Reference

Chapter 7. STL Iterators

Header Files for Iterators

All containers define their own iterator types, so you don't need a special header file for using iterators of containers. However, there are several definitions for special iterators, such as reverse iterators. These are introduced by the <iterator> header file,^[1] although you don't need to include this file in your program often. It is needed by containers to define their reverse iterator types and thus it is included by them.

Iterator Categories

Iterators are objects that can iterate over elements of a sequence. They do this via a common interface that is adapted from ordinary pointers (see the introduction in Section 5.3, page 83). Iterators follow the concept of pure abstraction: Anything ...