循环在initializer_list的范围内

Library::Library(std::initializer_list<Book> list) 
    : size{ list.size() }
{
    std::size_t i = 0;
    for (Book b : list)
    {
       insertBook(actual, b);
       actual = next(actual);
       size++;
    }
}
Library::Library(std::initializer_list<Book> li