# Which Data Structure Works in LIFO Fashion?

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Larry Thompson

When it comes to working with data structures, there are various types that cater to different needs. One particular type of data structure is the one that works on the principle of Last-In-First-Out (LIFO). In this article, we will explore this concept and discuss some common examples of data structures that follow the LIFO fashion.

## What is LIFO

LIFO stands for Last-In-First-Out, which means that the last element added to a data structure will be the first one to be removed. It follows a simple rule: “Last come, First out”. This concept is similar to a stack of plates, where you can only remove the topmost plate.

### Stack

The most commonly used data structure that follows LIFO fashion is the stack. A stack is an abstract data type that allows elements to be inserted and removed only from one end called the top.

The order in which elements are added or removed determines their position within the stack. Think of it as a vertical arrangement where you can only access or modify the topmost element.

To implement a stack in most programming languages, you can use arrays or linked lists. Arrays provide constant-time access to elements while linked lists offer flexibility in dynamic memory allocation.

Let’s take an example to understand how a stack works:

Step 1: Push ‘A’ onto the stack. Step 2: Push ‘B’ onto the stack. Step 3: Push ‘C’ onto the stack. Step 4: Pop an element from the stack.

It will be ‘C’. Step 5: Pop another element from the stack. It will be ‘B’. Step 6: Pop one more element from the stack. It will be ‘A’.

As you can see, the last element ‘C’ was the first one to be removed from the stack, followed by ‘B’ and then ‘A’. This is how LIFO works in a stack.

### Applications of Stack

The stack data structure finds its applications in various domains. Here are a few examples:

• Function Call Stack: When a function is called, its return address and local variables are stored in a stack frame. Once the function finishes executing, it is removed from the stack.
• Undo/Redo Operations: Many software applications implement undo/redo functionality using stacks.

Each action is stored as a state on the stack and can be undone or redone by popping or pushing elements respectively.

• Browser History: Web browsers use stacks to keep track of previously visited web pages. When you click on the back button, it pops the last page visited from the history stack.

### Other Data Structures with LIFO Behavior

In addition to stacks, there are other data structures that exhibit LIFO behavior:

• Deque (Double-Ended Queue): A deque allows insertion and removal of elements at both ends. However, when removing an element, it follows LIFO fashion.
• Recursive Function Calls: Recursive functions also exhibit LIFO behavior as each recursive call adds to the call stack until the base case is reached.

## In Conclusion

Data structures that work in LIFO fashion are essential for many applications. The stack is one such example that follows the Last-In-First-Out principle.

It provides a simple and efficient way to manage elements based on their order of insertion and removal. Understanding LIFO behavior is crucial for effectively solving problems and optimizing algorithms.