Question

Stack follows the ________ principle.

• A. Last-In-First-out
• B. First-In-First-out
• C. Enqueue - Dequeue
• D. Last-In-Last-out

Hint:

Stack $\rightarrow$ LIFO (Last-In, First-Out) $\rightarrow$ insertion/deletion at Top.
Queue $\rightarrow$ FIFO (First-In, First-Out) $\rightarrow$ insertion at Rear, deletion at Front.

Answer 1

The Correct Option is A

Concept:
A stack is a linear, ordered collection of elements with a restricted access discipline where all insertions and deletions are performed exclusively at one end, known as the top of the stack.

Step 1: Defining the Stack Access Mechanism:
Because elements enter and exit from the same end (the top), the item added most recently is always the first one to be removed.
This operational rule is called LIFO (Last-In-First-Out), or equivalently FILO (First-In-Last-Out).
Primary operations on a stack include:
- push: Inserting an element onto the top.
- pop: Removing the top element.

Step 2: Comparing with Other Structures:
- First-In-First-Out (FIFO) defines a Queue, where insertion takes place at the rear and deletion takes place at the front.
- Enqueue and Dequeue are the standard naming conventions for inserting and deleting elements in a Queue.
Final Answer:
The stack data structure operates strictly on the Last-In-First-Out (LIFO) principle.