value_type& value() const;
Requires: empty() == false.
Returns: A reference to the value_type subobject in the container_node_type object pointed to by ptr_.
Throws: Nothing.
key_type& key() const;
Requires: empty() == false.
Returns: A non-const reference to the key_type member of the value_type subobject in the container_node_type object pointed to by ptr_.
Throws: Nothing.
Remarks: Modifying the key through the returned reference is permitted.
mapped_type& mapped() const;
Requires: empty() == false.
Returns: A reference to the mapped_type member of the value_type subobject in the container_node_type object pointed to by ptr_.
Throws: Nothing.
allocator_type get_allocator() const;
Requires: empty() == false.
Returns: *alloc_.
Throws: Nothing.
explicit operator bool() const noexcept;
Returns: ptr_ != nullptr.
bool empty() const noexcept;
Returns: ptr_ == nullptr.