std::complex<T>::operator+(unary), operator-(unary)
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                    | (1) | ||
template< class T > std::complex<T> operator+( const std::complex<T>& val );  | 
(until C++20) | |
|   template< class T > constexpr std::complex<T> operator+( const std::complex<T>& val );  | 
(since C++20) | |
| (2) | ||
template< class T > std::complex<T> operator-( const std::complex<T>& val );  | 
(until C++20) | |
|   template< class T > constexpr std::complex<T> operator-( const std::complex<T>& val );  | 
(since C++20) | |
Implements the analogs of the unary arithmetic operators for complex numbers.
1) Returns the value of its argument
2) Negates the argument
Parameters
| val | - | the complex number argument | 
Return value
1) a copy of the argument, std::complex<T>(val)
2) negated argument, std::complex<T>(-val.real(), -val.imag())
See also
|   performs complex number arithmetic on two complex values or a complex and a scalar  (function template)  |