C++ Forward_list Library - forward_list() Function

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Description

The C++ constructor std::forward_list::forward_list() constructs a list with as many elements as in range of first to last.

Declaration

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

C++11

template <class InputIterator>
forward_list (InputIterator first, InputIterator last,
              const allocator_type& alloc = allocator_type());

Parameters

• first − Input iterator to initial position.

• last − Input iterator to final position.

• alloc − Allocator object.

Return value

Constructor never return value.

Exceptions

This member function never throws exception.

Time complexity

Linear i.e. O(n)

Example

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

#include <iostream>
#include <forward_list>

using namespace std;

int main(void) {

   forward_list<int> fl1 = {1, 2, 3, 4, 5};
   forward_list<int> fl2(fl1.begin(), fl1.end());

   cout << "List contains following elements" << endl;

   for (auto it = fl2.begin(); it != fl2.end(); ++it)
      cout << *it << endl;

   return 0;
}

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

List contains following elements
1
2
3
4
5