std::basic_string::size
From cppreference.com
                    
                                        
                    < cpp | string | basic string
                    
                                                            
                    |   size_type size() const;  | 
||
Returns the number of characters in the string, i.e. std::distance(begin(), end()). It is the same as length().
Contents | 
[edit] Parameters
(none)
[edit] Return value
the number of characters in the string
[edit] Complexity
Constant
[edit] See also
|    checks whether the string is empty   (public member function)  | |
|    returns the length of the string  (public member function)  | |
|    returns the maximum number of characters   (public member function)  | |