A stack is a special data structure where you only add, access, and remove elements from the top. A stack is also known as a last-in first-out (LIFO) structure. The Last thing to be added In to a stack is the First thing that comes Out of it.
In computer science, a stack is an abstract data type that serves as a collection of elements, with two principal operations:
- push, which adds an element to the collection, and
- pop, which removes the most recently added element that was not yet removed.
The order in which elements come off a stack gives rise to its alternative name, LIFO (last in, first out). Additionally, a peek operation may give access to the top without modifying the stack. The ADT operations on stack are: