4 A pointer can be explicitly converted to any integral type large enough to hold it. The mapping function is implementation-defined [Note: it is intended to be unsurprising to those who know the addressing structure of the underlying machine. ]
5 A value of integral type or enumeration type can be explicitly converted to a pointer. A pointer converted to an integer of sufficient size (if any such exists on the implementation) and back to the same pointer type will have its original value; mappings between pointers and integers are otherwise implementation-defined.
