Queue in Data Structure |Working of Queue and its Applications

In the realm of algorithms, you won’t make it far without reasonably comprehending how the queue data structure functions.

In this manual for the queue data structure we’ll stroll through:

What a queue is?

What they’re utilized for?

Ultimately we’ll wrap up by investigating how queues can be utilized in a certifiable turn of events?

QUEUE DATA STRUCTURE

A queue is used for storing the information. A queue is an ordered list with inserts at one end called the backend and deletes at one end called the frontend.

In the queue, the request in which information shows up is significant. the main component to be embedded is the first to be erased. consequently, it is called First in First out (FIFO) or Last in Last out(LILO).

At the point when a component is embedded in a line then it is called EnQueue, and when a component is erased from the line then it is called DeQueue.

DeQueueing an empty queue is referred to as underflow and EnQueueing a detail in a complete queue is referred to as overflow.

A Queue is what it sounds like. It’s a data structure that allows you to perform specific tasks (programs, steps, functions, etc.) by arranging them and taking the first item in the queue and executing it, followed by the next item and so on.

Thus a queue is a FIFO data structure i.e First in first out. Items may be rearranged in phrases of significance after they are input into the queue however, that does include a cost.

Why is a queue data structure called FIFO?

While you’re ready in ‘Q’, you pass and stand and await your flip and end your job. The same goes for the queue data structure, whoever/what is in place first gets a chance to use/complete their work next.

Just like waiting for an Immigration Security check-up. You can’t just directly go and ask officers to finish their checks. There is a procedure of checking needs to be completed earlier than the security.

FIFO is a manner of processing the information and Queue is the only support. You can design your data structure and make it work in the FIFO way, but why would you want to reinvent the wheel?

Real-world applications of a queue:

• Serving demands on a solitary common asset, similar to a printer, CPU task booking, and so on.
• In a genuine situation, Call Center telephone frameworks use Queues to hold individuals calling them all together until a help delegate is free. Handling of interrupts in real-time systems Interrupts are handled in the order in which they arrive, ie first come, first served. A real-world example of the queue can be a single-lane one-way road, where the vehicle enters first and exits first. More real-international examples may be visible as queues on the price tag home windows and bus stops.
• CPU task scheduling.

Operations of a queue:

• Create() :

Creates and initializes a new queue this is empty

• Enqueue(item) :

Adds a brand new object to the cease of the queue.

• Dequeue() :

Eliminates the component from the front of the line.

• isEmpty() :

Checks whether or not the queue is empty or not.

• isFull :

Checks regardless of whether the queue is full.

• Size() :

Returns the overall range of objects within the queue.

Types of queues:

There are four different types of queues:

• Simple Queue
• Circular Queue
• Priority Queue
• Double Ended Queue

In a circular queue, items at the end of the queue are bound to the beginning of the queue and vice versa. Items can then be added or removed from either end of the

queue as the program needs.

A priority queue is a collection of items where each item has been assigned a priority and the order in which items are removed depends on the following rules:

1. A component of higher need is handled before any component of lower need.

2. The components with a similar need are handled by the request in which they were added to the queue.

There can be two sorts of executions of the need queue :

· Ascending priority queue

· Descending priority queue

A collection of items into which items can be inserted at will and from which only the smallest item can be removed is called an ascending priority queue.

Only the largest item is removed from the priority-descending queue.

A priority queue is a data type completely separate from a queue. It doesn’t care about the order in which items are added (except in the special case of solving tiebreakers). When you queue an item, you also queue an associated priority. When it is time to check out an item, the item with the highest priority will be returned.

The double-ended queue is a more general form of queue data structure that allows for the insertion and deletion of elements from both ends, i. e. front and back.

Applications of Queue Data Structure:

1) When a resource is shared by multiple consumers. Examples are CPU scheduling and disk scheduling.

2) When information is transferred asynchronously among processes (information isn’t always obtained on the identical charge as it’s far sent). are IO Buffers, Pipes, File IO, etc.

ALGORITHMS

• INSERT-ITEM(QUEUE,FRONT,REAR,MAX,ITEM)

This algorithm is used to add or insert the item to QUEUE.

1. If (REAR = MAX) then

a. Display “Queue overflow”;

b. Return;

2. Otherwise

a. REAR:= REAR + 1;

b. QUEUE(REAR):= ITEM;

3. Return;

• REMOVE ITEM (QUEUE, FRONT, REAR, ITEM)

This algorithm is utilized to erase a thing from QUEUE..

1. If (FRONT = REAR + 1) then

a. Display “Queue underflow”;

b. Return;

2. Otherwise

a. ITEM:= QUEUE(FRONT);

b. FRONT := FRONT + 1;

3. Return;

EMPTY-CHECK(QUEUE, FRONT, REAR, EMPTY)

This algorithm is used to check whether

a QUEUE is EMPTY or not.

1. If (FRONT = REAR + 1) then

a. EMPTY:= true;

2. Otherwise

a. EMPTY:= false;

3. Return;

• FULL-CHECK(QUEUE, FRONT, REAR, MAX, FULL)

The algorithm is used to check whether

a QUEUE is full or not.

1. If ( REAR = MAX ) then

a. FULL:= true;

2. Otherwise

a. FULL:= false;

3. Return;

If you want to learn more about different types of Data structures you should get Data Structure & Algorithms course by Tutort Academy.

Tutort Academy is a leading E-Learning startup founded by NIT Trichy Alumni and Google, and Microsoft folks, they provide job-oriented courses for working professionals in the field of Data Science, Machine Learning, and Artificial Intelligence.