Data Structure
Networking
RDBMS
Operating System
Java
MS Excel
iOS
HTML
CSS
Android
Python
C Programming
C++
C#
MongoDB
MySQL
Javascript
PHP
Physics
Chemistry
Biology
Mathematics
English
Economics
Psychology
Social Studies
Fashion Studies
Legal Studies
- Selected Reading
- UPSC IAS Exams Notes
- Developer's Best Practices
- Questions and Answers
- Effective Resume Writing
- HR Interview Questions
- Computer Glossary
- Who is Who
queue::front() and queue::back() in C++ STL
In this article we will be discussing the working, syntax and examples of queue::front() and queue::back() functions in C++ STL.
What is a queue in C++ STL?
Queue is a simple sequence or data structure defined in the C++ STL which does insertion and deletion of the data in FIFO(First In First Out) fashion. The data in a queue is stored in continuous manner. The elements are inserted at the end and removed from the starting of the queue. In C++ STL there is already a predefined template of queue, which inserts and removes the data in the similar fashion of a queue.
What is queue::front()?
queue::front() is an inbuilt function in C++ STL which is declared in
Like in the above given figure, head i.e. 1 is the first element which has been entered in the queue and tail i.e. -4 is the last or the most recent element which is entered in the queue
Syntax
myqueue.front();
This function accepts no parameter
Return value
This function returns a reference to the element which is first inserted in the queue container.
Example
Input: queue<int> myqueue = {10, 20, 30, 40};
myqueue.front();
Output:
Front element of the queue = 10Example
#include <iostream>
#include <queue>
using namespace std;
int main(){
queue<int> Queue;
Queue.push(10);
Queue.push(20);
Queue.push(30);
Queue.push(40);
Queue.push(40);
cout<<"Element in front of a queue is: "<<Queue.front();
return 0;
}Output
If we run the above code it will generate the following output −
Element in front of a queue is: 10
What is queue::back()?
queue::back() is an inbuilt function in C++ STL which is declared in
Syntax
myqueue.back();
This function accepts no parameter
Return value
This function returns a reference to the element which is last inserted in the queue container.
Example
Input: queue<int> myqueue = {10, 20 30, 40};
myqueue.back();
Output:
Back element of the queue = 40Example
#include <iostream>
#include <queue>
using namespace std;
int main(){
queue<int> Queue;
Queue.push(10);
Queue.push(20);
Queue.push(30);
Queue.push(40);
Queue.push(50);
cout<<"Elements at the back of the queue is: "<<Queue.back();
return 0;
}Output
If we run the above code it will generate the following output −
Elements at the back of the queue is: 50
2K+ Views
