A stack is a fundamental data structure that is widely used in computer science. It follows the principle of “Last In, First Out” (LIFO), which means that the last element added to the stack is the first one to be removed. In this article, we will explore various scenarios where using a stack can be advantageous.

**1. Function Call Stack:**

One common use case of a stack is in function calls.

Whenever a function is called, its local variables and return address are stored in a stack frame. As each nested function call completes, its frame is popped off the stack, allowing the program to return to where it left off.

**2. Expression Evaluation:**

Stacks are often used to evaluate arithmetic expressions.

In this scenario, an expression is parsed and converted into postfix notation using a stack. The postfix expression can then be easily evaluated by iterating through it from left to right.

__Example:__

Consider the infix expression: 5 + 2 * 3

By converting it into postfix notation: 5 2 3 * +

We can evaluate it using a stack as follows:

– Push ‘5’ onto the stack. – Push ‘2’ onto the stack. – Push ‘3’ onto the stack.

– Pop ‘3’ and ‘2’, multiply them, and push the result (‘6’) onto the stack. – Pop ‘6’ and ‘5’, add them, and push the result (’11’) onto the stack. The final result is ’11’.

**3. Undo/Redo Operations:**

Stacks are useful for implementing undo/redo functionality in applications. Each action performed by a user can be pushed onto a stack, allowing for easy reversal or replaying of actions.

**4. Browser History:**

Web browsers maintain a history of visited pages using a stack-like data structure.

When a user navigates to a new page, the current page is pushed onto the stack. This allows the user to easily go back to the previous page by popping it from the stack.

**5. Depth-First Search (DFS):**

DFS is a graph traversal algorithm that explores as far as possible along each branch before backtracking. It can be implemented using a stack to keep track of visited nodes and the order in which they were visited.

## Conclusion:

In conclusion, stacks are incredibly useful data structures that find application in various domains of computer science. From function call management to expression evaluation and undo/redo operations, stacks provide an efficient way to store and retrieve data in a specific order.

Understanding when and how to use stacks can greatly improve your problem-solving skills. So, next time you encounter a problem where LIFO behavior is required, consider implementing a stack!