std::basic_string::rend, std::basic_string::crend
From cppreference.com
                    
                                        
                    < cpp | string | basic string
                    
                                                            
                    |   iterator rend();  | 
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|   const_iterator rend() const;  | 
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|   const_iterator crend() const;  | 
(since C++11) | |
Returns a reverse iterator to the character following the last character of the reversed string. It corresponds to the character preceding the first character of the non-reversed string. This character acts as a placeholder, attempting to access it results in undefined behavior.
Contents | 
[edit] Parameters
(none)
[edit] Return value
reverse iterator to the character following the last character
[edit] Complexity
Constant
[edit] See also
|    (C++11)  | 
   returns a reverse iterator to the beginning   (public member function)  |