How to make constructor accept all type of iterators?

Question

I am creating a custom Vector/ArrayList class. But i´m having troubles creating the iterative version of the constructor. The following code works, but the problem is when i

Answer 1

What you need to do is use SFINAE to constrain the template to only work when the template type is deduced to be an iterator type. Since you do arr_size{ static_cast(end - begin) } to initialize size this means that you expect the iterators to be random access. We can check for that using the iterator_category of std::iterator_traits Doing that gives you

template::iterator_category, 
                                            std::random_access_iterator_tag>, bool> = true>
ArrayList(ITER begin, ITER end) : arr_size{ static_cast(end - begin) }, arr_capacity{ arr_size }
{
    std::uninitialized_copy(begin, end, array = allocator.allocate(arr_size));
    first = array;
    last = array + arr_size - 1;
}