Queue
A queue in C++ is a data structure that follows the First-In-First-Out (FIFO) principle. It is similar to a real-life queue, where people line up and the first person to join is the first person to be served.
Include the necessary header file: To use the queue data structure in C++, you need to include the
<queue>
header file at the beginning of your code. This file contains the necessary implementations and functions for working with queues.Declare the queue: Next, declare the queue using the
std::queue
template class. You can specify the data type of the elements in the queue by providing it as a template argument. For example, to create a queue of integers, you can declare it asstd::queue<int> myQueue;
.Add elements to the queue: To add elements to the queue, you can use the
push()
function. For example, to add the integer value 10 to the queue, you can usemyQueue.push(10);
. This will add the element to the back of the queue.Access the front element: To access the element at the front of the queue (the element that will be removed next), you can use the
front()
function. For example, to retrieve the front element of the queue and store it in a variable calledfrontElement
, you can usefrontElement = myQueue.front();
.Remove elements from the queue: To remove the element at the front of the queue, you can use the
pop()
function. This will remove the front element and adjust the queue accordingly. For example, to remove the front element from the queue, you can usemyQueue.pop();
.Check if the queue is empty: To check if the queue is empty, you can use the
empty()
function. It returns a boolean value indicating whether the queue is empty or not. For example, to check if the queue is empty and store the result in a variable calledisEmpty
, you can useisEmpty = myQueue.empty();
.Get the size of the queue: To get the number of elements currently in the queue, you can use the
size()
function. It returns the size of the queue as an integer value. For example, to get the size of the queue and store it in a variable calledqueueSize
, you can usequeueSize = myQueue.size();
.
These are the basic steps for working with a queue in C++. By following these steps, you can create, modify, and access elements in a queue efficiently.