std::polar(std::complex)
From cppreference.com
                    
                                        
                    
                    
                                                            
                    | Defined in header  <complex> | ||
| template< class T >  complex<T> polar( const T& r, const T& theta = T()); | ||
Returns a complex number with magnitude r and phase angle theta.
The behavior is undefined if r is negative or NaN, or if theta is infinite.
Parameters
| r | - | magnitude | 
| theta | - | phase angle | 
Return value
a complex number determined by r and theta
Defect reports
The following behavior-changing defect reports were applied retroactively to previously published C++ standards.
| DR | Applied to | Behavior as published | Correct behavior | 
|---|---|---|---|
| LWG 2459 | C++98 | behavior unclear for some inputs | made undefined | 
| LWG 2870 | C++98 | default value of parameter theta not dependent | made dependent | 
See also
| returns the magnitude of a complex number (function template) | |
| returns the phase angle (function template) |