Mastering the C++17 STL

Algorithms that affect object lifetime

The <memory> header provides an obscure family of algorithms with names such as std::uninitialized_copy, std::uninitialized_default_construct, and std::destroy (for the full list, consult an online reference such as cppreference.com). Consider the following algorithm that uses explicit destructor calls to destroy the elements of a range:

    template<class T>    void destroy_at(T *p)    {      p->~T();    }    template<class FwdIt>    void destroy(FwdIt first, FwdIt last)    {      for ( ; first != last; ++first) {        std::destroy_at(std::addressof(*first));      }    }

Notice that std::addressof(x) is a convenient little helper function that returns the address of its parameter; it's exactly the same thing as &x except in the rare case that ...