C++ Deque Library - deque() Function

Description

The C++ default constructor std::deque::deque() constructs an empty deque with zero element. Storage requirement for this container is fulfilled by internal allocator.

Declaration

Following is the declaration for std::deque::deque() constructor form std::deque header.

C++98

explicit deque (const allocator_type& alloc = allocator_type());

C++11

explicit deque (const allocator_type& alloc = allocator_type());

Parameters

alloc − The allocator object.

Return value

Constructor never returns value.

Exceptions

This member function never throws exception.

Time complexity

Constant i.e. O(1)

Example

The following example shows the usage of std::deque::deque() constructor.

#include <iostream>
#include <deque>

using namespace std;

int main(void) {

   deque<int> d;

   cout << "Size of deque = " << d.size() << endl;

   return 0;
}

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

Size of deque = 0