_Complex_I
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C
Numerics
Complex number arithmetic
| Types and the imaginary constant | ||||||||||||||||
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| Manipulation | ||||||||||||||||
| Power and exponential functions | ||||||||||||||||
| Trigonometric functions | ||||||||||||||||
| Hyperbolic functions | ||||||||||||||||
| Defined in header <complex.h>
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| #define _Complex_I /* unspecified */ |
(since C99) | |
The _Complex_I macro expands to a value of type const float _Complex with the value of the imaginary unit.
Contents |
[edit] Notes
This macro may be used when I is not available, such as when it has been undefined by the application.
Unlike _Imaginary_I and CMPLX, use of this macro to construct a complex number may lose the sign of zero on the imaginary part.
[edit] Example
Run this code
#include <stdio.h> #include <complex.h> #undef I #define J _Complex_I / can be used to redefine I int main(void) { / can be used to construct a complex number double complex z = 1.0 + 2.0 * _Complex_I; printf("1.0 + 2.0 * _Complex_I = %.1f%+.1fi\n", creal(z), cimag(z)); / sign of zero may not be preserved double complex z2 = 0.0 + -0.0 * _Complex_I; printf("0.0 + -0.0 * _Complex_I = %.1f%+.1fi\n", creal(z2), cimag(z2)); }
Possible output:
1.0 + 2.0 * _Complex_I = 1.0+2.0i 0.0 + -0.0 * _Complex_I = 0.0+0.0i
[edit] References
- C23 standard (ISO/IEC 9899:2024):
- 7.3.1/4 _Complex_I (p: TBD)
- C17 standard (ISO/IEC 9899:2018):
- 7.3.1/4 _Complex_I (p: 136)
- C11 standard (ISO/IEC 9899:2011):
- 7.3.1/4 _Complex_I (p: 188)
- C99 standard (ISO/IEC 9899:1999):
- 7.3.1/2 _Complex_I (p: 170)
[edit] See also
| (C99) |
the imaginary unit constant i (macro constant) [edit] |
| (C99) |
the complex or imaginary unit constant i (macro constant) [edit] |
