Queue

In computer science, a queue is a linear data structure that follows the First In, First Out (FIFO) principle. This means that the first element added to the queue is the first one to be removed.

How a Queue Works

Think of a queue as a line of people waiting to enter a theater. The person who arrives first gets to enter the theater first, while the person who arrives later has to wait at the end of the line. Similarly, in a queue, elements are enqueued at the back and dequeued from the front.

Queue Operations

A queue typically supports two main operations:

• Enqueue: Adds an element at the back of the queue.
• Dequeue: Removes the element from the front of the queue.

Additionally, a queue can provide the following operations:

• Front: Returns the value of the front element without removing it.
• Empty: Checks if the queue is empty.

Implementing a Queue in C++

In C++, you can use the std::queue container class to implement a queue. The std::queue class is a container adapter that uses a deque as its underlying container.

Here's an example of creating and using a queue in C++:

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#include <iostream>

#include <queue>

​

int main() {

  // Creating a queue

  std::queue<int> myQueue;

​

  // Enqueuing elements

  myQueue.push(1);

  myQueue.push(2);

  myQueue.push(3);

​

  // Checking if the queue is empty

  bool empty = myQueue.empty();

​

  // Getting the front element

  int frontElement = myQueue.front();

​

  // Dequeuing elements

  myQueue.pop();

​

  return 0;

}