Section 21.9 Container Classes and Iterators

• Items are returned from a queue in first-in, first-out (FIFO) order—the first item inserted in the queue is the first item removed from the queue.

• Container classes (also called collection classes) are designed to hold collections of objects. Container classes commonly provide services such as insertion, deletion, searching, sorting, and testing an item to determine whether it is a member of the collection.

• It is common to associate iterators with container classes. An iterator is an object that “walks through” a collection, returning the next item (or performing some action on the next item).