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Stacks

Introduction

A stack is an ordered list that follows the Last-In-First-Out (LIFO) principle. This means that the last element added to the stack will be the first one to be removed. Stacks are widely used in various applications such as function call management, expression evaluation, backtracking algorithms, and more.

Key Operations

A stack typically supports the following operations:

  • Push: Add an element to the top of the stack.
  • Pop: Remove and return the top element from the stack.
  • Peek/Top: Return the top element without removing it.
  • isEmpty: Check if the stack is empty.
  • Size: Return the number of elements in the stack.

Stack Implementation

Stacks can be implemented using arrays (or lists) and linked lists. Most programming languages provide built-in support for stacks, either directly or through libraries.

Advantages and Disadvantages

Advantages: - Simple and easy to implement. - Efficient for LIFO operations.

Disadvantages: - Limited access: Only the top element can be accessed directly. - Fixed size if implemented using arrays (unless using dynamic arrays).