std::real(std::complex) - cppreference.com (original) (raw)
| Defined in header | | | | ---------------------------------------------------------------------------------------------------------------- | | --------------------------- | | (1) | | | | template< class T > T real( const std::complex<T>& z ); | | (until C++14) | | template< class T > constexpr T real( const std::complex<T>& z ); | | (since C++14) | | Additional overloads (since C++11) | | | | Defined in header | | | | (A) | | | | float real( float f ); double real( double f ); long double real( long double f ); | | (until C++14) | | constexpr float real( float f ); constexpr double real( double f ); constexpr long double real( long double f ); | | (since C++14) (until C++23) | | template< class FloatingPoint > constexpr FloatingPoint real( FloatingPoint f ); | | (since C++23) | | (B) | | | | template< class Integer > double real( Integer i ); | | (until C++14) | | template< class Integer > constexpr double real( Integer i ); | | (since C++14) |
- Returns the real part of the complex number z, i.e. z.real().
| A,B) Additional overloads are provided for all integer and floating-point types, which are treated as complex numbers with zero imaginary part. | (since C++11) |
|---|
[edit] Parameters
| z | - | complex value |
|---|---|---|
| f | - | floating-point value |
| i | - | integer value |
[edit] Return value
- The real part of z.
A) f.
B) static_cast<double>(i).
[edit] Notes
The additional overloads are not required to be provided exactly as (A,B). They only need to be sufficient to ensure that for their argument num:
- If num has a standard(until C++23) floating-point type
T, then std::real(num) has the same effect as std::real(std::complex<T>(num)). - Otherwise, if num has an integer type, then std::real(num) has the same effect as std::real(std::complex<double>(num)).