C++ How to Program, 10/e

... uses stack function top to retrieve the top element of the stack for output. Line 56 uses function pop (available in each adapter class) to remove the top element of the stack. Function pop does not return a value.

15.7.2 queue Adapter

A queue is similar to a waiting line. The item that has been in the queue the longest is the next one removed—so a queue is referred to as a first-in, first-out (FIFO) data structure. Class queue (from header <queue>) enables insertions only at the back of the underlying data structure and deletions only from the front. A queue can store its elements in objects of the Standard Library’s list or deque containers. By default, a queue is implemented with a deque. The common queue operations are push to insert an element ...