Queue Emplace in C++ STL

In this article we will be discussing the working, syntax and examples of queue::emplace() function 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::emplace()?

queue::emplace() is an inbuilt function in C++ STL which is declared in  header file. queue::emplace() is used to insert or emplace a new element in the queue container. As the functionality of the queue structure is that the element inserted to the end of the structure, to emplace() calls the emplace_back() for the successful insertion of the element at the end of the queue container.

Syntax

myqueue.emplace(value_type &t);

This function accepts one parameter, i.e. the element which is to be inserted in the associated queue container.

Return value

This function returns nothing.

Example

Input: queue<int> myqueue = {10, 20, 30, 40};
   myqueue.emplace(50);
Output:
   Elements In the queue = 10 20 30 40 50

Example

 Live Demo

#include <iostream>
#include <queue>
using namespace std;
int main (){
   queue<int> Queue;
   Queue.emplace(10);
   Queue.emplace(20);
   Queue.emplace(30);
   Queue.emplace(40);
   Queue.emplace(50);
   cout<<"Elements in Queue are: ";
   while(!Queue.empty()){
      cout << ' ' << Queue.front();
      Queue.pop();
   }
   return 0;
}

Output

If we run the above code it will generate the following output −

Elements in Queue are: 10 20 30 40 50

Example

 Live Demo

#include <iostream>
#include <queue>
using namespace std;
int main(){
   queue<string> Queue;
   Queue.emplace("Welcome");
   Queue.emplace("To");
   Queue.emplace("Tutorials");
   Queue.emplace("Point");
   cout<<"String is : ";
   while (!Queue.empty()){
      cout << ' ' << Queue.front();
      Queue.pop();
   }
   return 0;
}

Output

If we run the above code it will generate the following output −

String is : Welcome To Tutorials Point