137 class RandomIterator {
148     RandomIterator() : my_ptr(nullptr) {}  in RandomIterator()  function
149     explicit RandomIterator ( T * ptr ) : my_ptr(ptr){}  in RandomIterator()  function
150     RandomIterator ( const RandomIterator& r ) : my_ptr(r.my_ptr){}  in RandomIterator()  function
152     RandomIterator& operator++ () { ++my_ptr; return *this; }
153     RandomIterator operator++(int) {
154         RandomIterator result = *this;
158     RandomIterator& operator--() { --my_ptr; return *this; }
159     RandomIterator operator--(int) {
160         RandomIterator result = *this;
165     bool operator== ( const RandomIterator& r ) const { return my_ptr == r.my_ptr; }
166     bool operator!= ( const RandomIterator& r ) const { return my_ptr != r.my_ptr; }
167     difference_type operator- (const RandomIterator &r) const {return my_ptr - r.my_ptr;}
168     RandomIterator operator+ (difference_type n) const {return RandomIterator(my_ptr + n);}
169     bool operator< (const RandomIterator &r) const {return my_ptr < r.my_ptr;}
170     bool operator> (const RandomIterator &r) const {return my_ptr > r.my_ptr;}
171     bool operator<=(const RandomIterator &r) const {return my_ptr <= r.my_ptr;}
172     bool operator>=(const RandomIterator &r) const {return my_ptr >= r.my_ptr;}
174     RandomIterator& operator+=( difference_type n ) {
178     RandomIterator& operator-=( difference_type n ) {
183     friend RandomIterator operator+( difference_type n, RandomIterator it ) {
184         return RandomIterator(it.my_ptr + n);
186     RandomIterator operator-( difference_type n ) const {
187         return RandomIterator(my_ptr - n);