Question

A stack follows ______ principle.

• A. FIFO
• B. LIFO
• C. Enqueue-Dequeue
• D. LILO

Hint:

Think of everyday examples to remember:
- Stack = LIFO (Stack of plates, Undo/Redo operations, Function call stack).
- Queue = FIFO (Line at a ticket counter, Print jobs).

Answer 1

The Correct Option is B

Step 1: Understanding the Question:
The question asks to identify the fundamental ordering principle followed by a Stack data structure for its insertion and deletion operations.

Step 2: Key Concepts of Stack and Queue:
- Stack: A restricted linear data structure where all insertions and deletions are performed at the same end, called the "top".
- Queue: A linear data structure where insertions occur at one end (rear) and deletions occur at the opposite end (front).

Step 3: Detailed Explanation:
- Let us analyze the different acronym principles:
- LIFO (Last-In, First-Out): This principle means that the element inserted most recently is the first one to be removed. This is the defining behavior of a stack. For example, a stack of plates: the last plate placed on top is the first one to be taken off.
- FIFO (First-In, First-Out): This principle states that the first element inserted is the first one to be removed. This is the operational rule of a Queue (e.g., people standing in a line).
- LILO (Last-In, Last-Out): This is logically identical to the FIFO principle and is not typically used as a standard term for stacks.
- Enqueue-Dequeue: These are names of operations performed on a Queue, not behavioral principles of a stack.
- Hence, a stack strictly follows the LIFO principle.

Step 4: Final Answer:
A stack follows the LIFO (Last-In, First-Out) principle.
Hence, option (B) is the correct choice.