std::istream_iterator::operator*, operator->
From cppreference.com
                    
                                        
                    < cpp | iterator | istream iterator
                    
                                                            
                    |   const T& operator*() const;  | 
(1) | |
|   const T* operator->() const;  | 
(2) | |
Returns a pointer or a reference to the current element.
The behavior is undefined if the iterator is end-of-stream iterator.
[edit] Parameters
(none)
[edit] Return value
A pointer or a reference to the current element.
[edit] Exceptions
(none)