STL offers a set of extremely useful container types. A container is a data structure that contains a collection of elements. The container manages the memory of the elements it holds. This means that we don't have to explicitly create and delete our objects that we put in a container. We can pass objects created on the stack to a container and the container will copy and store them on the free store.
Iterators are used for accessing elements in containers, and are therefore a fundamental concept for understanding STL. The iterator concept is covered in Chapter 5, A Deeper Look at Iterators. For this chapter, it's enough to know that an iterator can be thought of as a pointer to an element and that the iterators have different operators defined depending on the container they belong to. For example, array-like data structures provide random access iterators...
