Anteckning
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Retrieves the real part of a complex number.
Syntax
double creal( _Dcomplex z );
float crealf( _Fcomplex z );
long double creall( _Lcomplex z );
#define creal(X) // Requires C11 or later
float creal( _Fcomplex z ); // C++ only
long double creal( _Lcomplex z ); // C++ only
Parameters
z
A complex number.
Return value
The real part of z.
Remarks
Because C++ allows overloading, you can call overloads of creal that take _Fcomplex or _Lcomplex values, and return float or long double values. In a C program, unless you're using the <tgmath.h> macro to call this function, creal always takes a _Dcomplex value and returns a double value.
If you use the <tgmath.h> creal() macro, the type of the argument determines which version of the function is selected. See Type-generic math for details.
Requirements
| Routine | C header | C++ header |
|---|---|---|
creal, crealf, creall |
<complex.h> | <ccomplex> |
creal macro |
<tgmath.h> |
The _Fcomplex, _Dcomplex, and _Lcomplex types are Microsoft-specific equivalents of the unimplemented native C99 types float _Complex, double _Complex, and long double _Complex, respectively. For more compatibility information, see Compatibility.
See also
Alphabetical function reference
_Cbuild, _FCbuild, _LCbuild
norm, normf, norml
cproj, cprojf, cprojl
conj, conjf, conjl
cimag, cimagf, cimagl
carg, cargf, cargl
cabs, cabsf, cabsl