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# Difference between Stack and Queue Data Structures

Last Updated on April 18, 2023 by Prepbytes

Data structures are an essential part of computer science and programming. Two fundamental data structures that are frequently used are stacks and queues. These data structures provide a way to store and retrieve data in a specific order. In this article, we will discuss stack and queue data structures and the difference between stack and queue. Letâ€™s start with baby steps and work our way up to our main topic â€śStack And Queue Differenceâ€ť. So, without any further delay, letâ€™s move on to our next section.

## What is Stack Data Structure?

A stack is a linear data structure that follows the Last-In-First-Out (LIFO) principle. There are two main operations in the stack: push and pop. The push operation adds an element to the top of the stack, and the pop operation removes the topmost element from the stack. The elements are stored in sequential order, and the top of the stack refers to the element that was most recently added.

Stacks are widely used in computer science and programming to manage function calls, undo-redo operations, expression evaluation, and more. For example, when a function is called, the parameters and local variables are pushed onto the stack, and when the function returns, the values are popped off the stack. The stack is also used in undo-redo operations, where the previous states of an object are pushed onto the stack, and the current state is popped off the stack to undo the changes.

## What is Queue Data Structure?

A queue is a linear data structure that follows the First-In-First-Out (FIFO) principle. There are two main operations in the queue: enqueue and dequeue. The enqueue operation adds an element to the rear end of the queue, and the dequeue operation removes the frontmost element from the queue. The elements are stored in sequential order, and the front of the queue refers to the element that was first added.

Queues are widely used in computer science and programming to manage job scheduling, messaging systems, printer queue, and more. For example, in a job scheduling system, the jobs are added to the queue, and the job with the highest priority is dequeued first. In a messaging system, the messages are added to the queue, and the messages are dequeued in the order they were received.

Now, letâ€™s move on to our main section which is the difference between stack and queue data structures.

## Difference Between Stack and Queue Data Structures.

Given below is the table showing stack and queue difference.

Parameters Stack Data Structure Queue Data Structure
Basics Stack is a linear data structure. The elements are inserted or removed from the same end. Queue is also a linear data structure. The elements are inserted or removed from two different ends.
Working It follows LIFO (Last in first out) property. It follows FIFO (First in first out) property.
Pointers Stack has only one pointer called top which points the address of the topmost element of the stack Queue has two pointers i.e. front and rear.
Operations Insertion is called push. Insertion is called enqueue
Operations Deletion is called pop. Deletion is called Dequeue.
Uses Stack is used for solving recursive problems Queue is used for solving sequential problems.

In summary, the main difference between stack and queue data structures is the order in which the elements are accessed and removed. In a stack, the last element added is the first one to be removed, while in a queue, the first element added is the first one to be removed.

Conclusion
In this blog, we had discussed completely about Stack and Queue, the difference between stack and queue, how stack and queue worked, and discussed the table containing the key points for the stack and queue difference. Stack and Queue are very vast topics in data structures, there are lots more to discover from the outside. Practice more on data structures like stack and queue to become a master in data structures on our platform MYCODE | Competitive Programming.

## FAQs

Here are some frequently asked questions on stack and queue.

Q1: What is the difference in access between a stack and a queue?
Answer: In a stack, only the top element is accessible at any given time, while in a queue, only the front element is accessible at any given time.

Q2: What is the main advantage of using a stack over a queue?
Answer: The main advantage of using a stack is that it allows for efficient memory management and can help prevent stack overflow errors.

Q3: What is the main advantage of using a queue over a stack?
Answer: The main advantage of using a queue is that it provides an ordered sequence of items, allowing for predictable behavior in systems that require such ordering.

Q4: Can a stack or a queue contain duplicate elements?
Answer: Both stacks and queues can contain duplicate elements.

Q5: Can elements be inserted or removed from the middle of a stack or queue?
Answer: No, elements cannot be inserted or removed from the middle of a stack or queue. They can only be added to the top or rear end, respectively, and removed from the top or front end, respectively.

Q6: Are stacks and queues used in real-world applications?
Answer: Yes, stacks and queues are used in a wide variety of real-world applications, ranging from operating systems and databases to video games and web applications.