C++ Queue Library - emplace() Function

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Description

The C++ function std::queue::emplace() constructs and inserts new element at the end of queue. The new element is constructed in-place i.e. without performing move or copy operation.

This member function effectively calls emplace_back function of underlying container.

Declaration

Following is the declaration for std::queue::emplace() function form std::queue header.

C++11

template <class... Args> void emplace (Args&&... args);

Parameters

args − Arguments forwarded to construct the new element.

Return value

None

Time complexity

Logarithmic in the size of the container.

Example

The following example shows the usage of std::queue::emplace() function.

#include <iostream>
#include <queue>

using namespace std;

int main(void) {
   queue<int> q;

   for (int i = 0; i < 5; ++i)
      q.emplace(i + 1);

   cout << "Contents of queue" << endl;
   while (!q.empty()) {
      cout << q.front() << endl;
      q.pop();
   }

   return 0;
}

Let us compile and run the above program, this will produce the following result −

Contents of queue
1
2
3
4
5