Putting it all together

Putting together everything we've learned in this chapter, we can now write code like the following example. In this example, we're implementing our own list_of_ints with our own iterator class (including a const-correct const_iterator version); and we're enabling it to work with the standard library by providing the five all-important member typedefs.

    struct list_node {
      int data;
      list_node *next;
    };

    template<bool Const>
    class list_of_ints_iterator {
      friend class list_of_ints;
      friend class list_of_ints_iterator<!Const>;

      using node_pointer = std::conditional_t<Const, const list_node*,
        list_node*>;
      node_pointer ptr_;

      explicit list_of_ints_iterator(node_pointer p) : ptr_(p) {}
    public:
      // Member typedefs required by std::iterator_traits
      using difference_type = std::ptrdiff_t;
      using value_type = int;
      using pointer = std::conditional_t<Const, const int*,...