Output Iterators

• Specialized write_only forward iterator:

// no comparison logic

// write-only element access (lvalue only)
value_type& operator *  ();                // dereference operator

// motion
Iterator&   operator ++ ();                // prefix increment
Iterator&   operator ++ (int);             // postfix increment

// proper type 
            Iterator  ()                   // constructor
            ~Iterator ()                   // destructor
            Iterator  (const Iterator& );  // copy constructor
//  no assignment operator