Stack Data Structure
What is a stack?
A stack is an abstract data type that holds an ordered, linear sequence of items
A stack is a last in, first out (LIFO) structure
A real-life example is a stack of plates:
You can only take a plate from the top of the stack, and you can only add a plate to the top of the stack
If you want to reach a plate that is not on the top of the stack, you need to remove all of the plates that are above that one
In a stack data structure, you can only access the element on the top of the stack
The element that was added last will be the one to be removed first
To implement a stack, you need to maintain a pointer to the top of the stack (the last element to be added)
What are the operations of a stack?
The main stack operations are:
push(data) - adds an element to the top of the stack
pop( ) - removes an element from the top of the stack
peek( ) - returns a copy of the element on the top of the stack without removing it
is_empty( ) - checks whether a stack is empty
is_full( ) - checks whether a stack is at maximum capacity when stored in a static (fixed-size) structure
How does a stack work?
Below is a visualisation of how a stack works