std::complex::real
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   constexpr T real() const;  | 
(1) | |
|   void real( T value );  | 
(2) | |
Accesses the real part of the complex number.
1) Returns the real part.
2) Sets the real part to 
value.[edit] Parameters
| value | - | the value to set the real part to | 
[edit] Return value
1) The real part.
2) (none)
[edit] See also
|    accesses the imaginary part of the complex number  (public member function)  | |