C++ Deque Library - deque() Function

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Description

The C++ copy constructor std::deque::deque() constructs a deque with copy of each elements present in existing container. 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

deque (const deque& x);

C++11

deque (const deque& x);
deque (const deque& x, const allocator_type& alloc);

Parameters

• alloc − The allocator object.

• x − Another deque object of same type.

Return value

Constructor never returns value.

Exceptions

This member function never throws exception.

Time complexity

Linear i.e. O(n)

Example

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

#include <iostream>
#include <deque>

using namespace std;

int main(void) {

   deque<int> d1 = {1, 2, 3, 4, 5};
   deque<int> d2(d1);

   cout << "Contents of deque are" << endl;

   for (int i = 0; i < d2.size(); ++i)
      cout << d2[i] << endl;

   return 0;
}

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

Contents of deque are
1
2
3
4
5