An Introduction to Data Structures

Stacks and Queues

Stacks and queues are special data types that allow insertion and remove of items at the ends only, not in the middle.
A stack lets you insert and remove elements at one end only, traditionally called the top of the stack.
To visualize a stack, think of a stack of books.
Since items can only be added or removed from the top of the stack, they are removed in the order that is opposite from the order they were added.
This is called last in, first out or LIFO order.
The addition and removal operations are called push and pop.