Stacks are widely used in computer science and real-world applications due to their Last-In, First-Out (LIFO) behavior. They provide efficient solutions for problems involving reversibility, function calls, and data backtracking. Below are some key applications of stacks:

1. Memory Management (Function Call Stack)

• Manages function calls in programming by pushing function calls onto the stack and popping them after execution.
• Enables recursion, where each function call gets a new stack frame.
• Helps in tracking local variables and return addresses for each function.

2. Expression Evaluation & Syntax Parsing

• Ensures correct execution order in arithmetic expressions by managing operator precedence.
• Used in parsing programming languages, particularly for validating brackets and expressions.
• Converts infix expressions to postfix notation, which is easier for computers to evaluate.

3. Undo/Redo Mechanism in Software

• Stores user actions as stack operations in text editors, image editors, and IDEs.
• Pressing Undo pops the last action from the stack and reverses it.
• Redo re-applies an action by pushing it back onto the stack.

4. Backtracking Algorithms

• Used in problems that require trying different possibilities and reverting if needed.
• Common in Sudoku solvers, maze pathfinding, and the N-Queens problem.
• Stores previous states, allowing the algorithm to revert to an earlier position when a dead end is reached.

5. Depth-First Search (DFS) in Graphs

• DFS explores a graph deep into one path before backtracking.
• Uses a stack to store nodes that need to be visited.
• Helps in finding connected components, cycle detection, and solving maze problems.

6. Web Page History (Back Button in Browsers)

• Every visited web page is pushed onto the history stack.
• Clicking "Back" pops the last visited page, returning the user to the previous one.
• This method allows users to navigate webpages in reverse order efficiently.

Stacks are a simple yet powerful data structure with diverse applications in memory management, problem-solving, and algorithm optimization. Their efficiency in handling reversibility and sequential access makes them essential in both software development and real-world computing systems.