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The Standard Template Library (STL) in C++ provides a collection of powerful data structures and algorithms, among which the queue is a fundamental and widely-used container. A queue is a First-In-First-Out (FIFO) data structure, where elements are added at the back and removed from the front. This behavior makes queues ideal for scenarios like task scheduling, buffering, and breadth-first search algorithms. In this guide, we will explore the queue container in the C++ STL, covering its basic operations, usage, and practical examples to help you understand and utilize this essential data structure effectively.<\/p>\n
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A queue is a container adapter in the C++ Standard Template Library (STL) that operates on a First-In-First-Out (FIFO) basis. Elements are inserted at the back (end) and removed from the front.<\/p>\n
Given below are the operations of the queue:<\/strong><\/p>\n Enqueue:<\/strong> This function is used to add an element to the rear end of the queue. If the queue is completely filled, then it will be in an overflow condition. The time complexity of the enqueue is O(1).<\/p>\n<\/li>\n Dequeue:<\/strong> This function is used to remove an element from the front end of the queue. If the queue is empty, then it will be in an underflow condition. The time complexity of the dequeue is O(1).<\/p>\n<\/li>\n Front:<\/strong> This function returns the front element of the queue. The time complexity of this function is O(1).<\/p>\n<\/li>\n Rear:<\/strong> This function returns the last element of the queue. The time complexity of this function is O(1).<\/p>\n<\/li>\n<\/ul>\n In C++, the STL queue provides the functionality of a queue data structure. First we need to include a queue header file. After importing the header file we\u2019ll create the queue with a suitable data type. push():<\/strong> This operation is used to insert an element at the end of the queue.<\/p>\n pop():<\/strong> This operation is used to remove an element from the end of the queue.<\/p>\n front():<\/strong> This operation is used to return the first element of the queue.<\/p>\n back():<\/strong> This operation is used to return the last element of the queue.<\/p>\n empty():<\/strong> This operation is used to check whether the queue is empty or not.<\/p>\n size():<\/strong> This operation is used to return the size of the queue.<\/p>\n\t\t\t\t\t\t\n
Queue STL:<\/h3>\n
\nA Queue is a linear data structure. Queue follows the FIFO rule i.e. First in First out. In other words we can say the element that goes in first is the element that comes out first.
\nFor Example A ticket Queue outside a cinema hall where the person enters the queue first will get the ticket first. <\/p>\n![\"\"](\"https:\/\/prepbytes-misc-images.s3.ap-south-1.amazonaws.com\/assets\/1656309037245-Image-01.png\")
<\/p>\nCreate STL queue in C++:<\/h3>\n
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\n#include <\/code><\/p>\n<\/li>\n
\nqueue q<\/code>
\nFor example:
\nqueue q;<\/code>
\nqueue q1;<\/code><\/p>\n<\/li>\n<\/ul>\nC++ queue STL Operations:<\/h3>\n