imaginary

 

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Complex number arithmetic

Types and the imaginary constant
complex (哋它亢99) _Complex_I (哋它亢99)     CMPLX (哋它亢11)	imaginary (哋它亢99) _Imaginary_I (哋它亢99) I (哋它亢99)
Manipulation
cimag (哋它亢99) creal (哋它亢99) carg (哋它亢99)	cabs (哋它亢99) conj (哋它亢99) cproj (哋它亢99)
Power and exponential functions
cexp (哋它亢99) clog (哋它亢99)	cpow (哋它亢99) csqrt (哋它亢99)
Trigonometric functions
ccos (哋它亢99) csin (哋它亢99) ctan (哋它亢99)	cacos (哋它亢99) casin (哋它亢99) catan (哋它亢99)
Hyperbolic functions
ccosh (哋它亢99) csinh (哋它亢99) ctanh (哋它亢99)	cacosh (哋它亢99) casinh (哋它亢99) catanh (哋它亢99)

 

Defined in header <complex.h>
#define imaginary _Imaginary		(since 哋它亢99)

This macro expands to the keyword _Imaginary.

This is a convenience macro that makes it possible to use float imaginary, double imaginary, and long double imaginary as an alternative way to write the three pure imaginary C types float _Imaginary, double _Imaginary, and long double _Imaginary

As with any pure imaginary number support in C, this macro is only defined if the imaginary numbers are supported.

A compiler that defines __STDC_IEC_559_COMPLEX__ is not required to support imaginary numbers. POSIX recommends checking if the macro _Imaginary_I is defined to identify imaginary number support.	(since 哋它亢99) (until 哋它亢11)
Imaginary numbers are supported if __STDC_IEC_559_COMPLEX__ is defined.	(since 哋它亢11)

Notes

Programs are allowed to undefine and perhaps redefine the imaginary macro.

To date, only Oracle C compiler is known to have implemented imaginary types.

Example

Run this code

#include <stdio.h>
#include <complex.h>
 
int main(void)
{
    double imaginary i = -2.0*I; // pure imaginary
    double f = 1.0; // pure real
    double complex z = f + i; // complex number
    printf("z = %.1f%+.1fi\n", creal(z), cimag(z));
}

Output:

z = 1.0-2.0i

References

• 哋它亢17 standard (ISO/IEC 9899:2018):

• 7.3.1/5 imaginary (p: 136)

• G.6/1 imaginary (p: 391-392)

• 哋它亢11 standard (ISO/IEC 9899:2011):

• 7.3.1/5 imaginary (p: 188)

• G.6/1 imaginary (p: 537)

• 哋它亢99 standard (ISO/IEC 9899:1999):

• 7.3.1/3 imaginary (p: 170)

• G.6/1 imaginary (p: 472)

See also

complex (哋它亢99)

complex type macro (keyword macro)