Queue in Dart Programming

A Queue is a linear data structure that follows the First In, First Out (FIFO) principle. It organizes elements in a sequence where the first element added to the queue is the first one to be removed. Dart provides a built-in Queue class within the dart:collection library, allowing developers to create, manipulate, and access queues efficiently.
For Example, Imagine it as a line of people waiting for a service – the first person who joins the line is the first one to be served, and as people join the line, they join at the end and wait for their turn.

In the below PDF we discuss about Dart Queues in detail in simple language, Hope this will help in better understanding.

Dart Programming

Implementing Queues in Dart:

Dart, being a versatile and modern programming language, provides built-in support for queues through its collection libraries. The dart:collection library offers a class called Queue, which can be utilized to create and manipulate queues effortlessly.

Here’s how you can create a queue in Dart:

import 'dart:collection';

void main() {
Queue<int> myQueue = Queue<int>();

// Adding elements to the queue

// Accessing and removing elements from the queue
print(myQueue.removeFirst()); // Outputs: 10
print(myQueue.removeFirst()); // Outputs: 20

In this example, we import the dart:collection library, create a Queue of integers, and then add elements to it using the add method. The removeFirst method is used to access and remove elements from the front of the queue.

Operations on Queues:

Queues support several operations that allow for efficient manipulation of data. Some of the common operations include:

  • Enqueue: Adding an element to the end of the queue.
  • Dequeue: Removing an element from the front of the queue.
  • Peek: Viewing the element at the front of the queue without removing it.
  • isEmpty: Checking if the queue is empty.
  • length: Getting the number of elements in the queue.

Let’s see how these operations are performed in Dart:

void main() {
Queue<String> myQueue = Queue<String>();

// Enqueue operation

// Dequeue operation
print(myQueue.removeFirst()); // Outputs: Apple

// Peek operation
print(myQueue.first); // Outputs: Banana

// Checking if the queue is empty
print(myQueue.isEmpty); // Outputs: false

// Getting the number of elements in the queue
print(myQueue.length); // Outputs: 1

Applications of Queues:

Queues find applications in various areas of computer science and software development, including:

  1. Task Scheduling: Managing tasks to be executed in the order they were received.
  2. Breadth-First Search: Traversing nodes in a graph level by level.
  3. Buffering: Handling requests or data packets in networking.
  4. Printer Spooling: Managing print jobs in the order they are submitted.


In Conclusion, Queues are essential data structures in Dart programming, offering efficient storage and retrieval mechanisms for managing elements in a FIFO manner. By understanding how to implement and utilize queues in Dart, developers can enhance the efficiency and performance of their applications, especially in scenarios involving task scheduling, message processing, graph traversal, and CPU scheduling.

Related Question

A Queue in Dart is a collection that operates on the principle of First-In-First-Out (FIFO), meaning the first element added to the queue is the first one to be removed.

The main difference is in their behavior. A List in Dart is an ordered collection that allows duplicates and provides random access to elements, while a Queue is a collection that follows the FIFO principle, allowing efficient insertion and removal of elements from both ends.

You should use a Queue when you need to manage elements based on the FIFO principle, especially when dealing with tasks such as scheduling, event handling, or implementing algorithms like breadth-first search (BFS).

Yes, Queues in Dart are resizable. They automatically grow in size to accommodate new elements as needed.

Yes, Queues in Dart can hold elements of different data types, as Dart is a dynamically typed language. However, it’s a good practice to maintain consistency in data types for better code readability and maintainability.


OOPS in Dart Object-Oriented Programming

Maps in Dart A Map

Set in Dart A Set

Dart Lists A Dart list

Strings in Dart A Dart

Functions in Dart In Dart,

Exception Handling in Dart Exception

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