cargf, carg, cargl
From cppreference.com
C
Concurrency support (C11)
Complex number arithmetic
Types and the imaginary constant
Manipulation
Power and exponential functions
Trigonometric functions
Hyperbolic functions
Defined in header
<complex.h>
float cargf( float complex z );
(1)
(since C99)
double carg( double complex z );
(2)
(since C99)
long double cargl( long double complex z );
(3)
(since C99)
Defined in header
<tgmath.h>
#define carg( z )
(4)
(since C99)
1-3) Computes the argument (also called phase angle) of
z, with a branch cut along the negative real axis.4) Type-generic macro: if
z has type long double complex , long double imaginary , or long double, cargl is called. If z has type float complex , float imaginary , or float, cargf is called. If z has type double complex , double imaginary , double, or any integer type, carg is called.[edit] Parameters
z
-
complex argument
[edit] Return value
If no errors occur, returns the phase angle of z in the interval [−π; π].
Errors and special cases are handled as if the function is implemented as atan2 (cimag (z), creal (z))
[edit] Example
Run this code
#include <stdio.h> #include <complex.h> int main(void) { double complex z1 = 1.0+0.0*I; printf ("phase angle of %.1f%+.1fi is %f\n", creal (z1), cimag (z1), carg(z1)); double complex z2 = 0.0+1.0*I; printf ("phase angle of %.1f%+.1fi is %f\n", creal (z2), cimag (z2), carg(z2)); double complex z3 = -1.0+0.0*I; printf ("phase angle of %.1f%+.1fi is %f\n", creal (z3), cimag (z3), carg(z3)); double complex z4 = conj (z3); // or CMPLX(-1, -0.0) printf ("phase angle of %.1f%+.1fi (the other side of the cut) is %f\n", creal (z4), cimag (z4), carg(z4)); }
Output:
phase angle of 1.0+0.0i is 0.000000 phase angle of 0.0+1.0i is 1.570796 phase angle of -1.0+0.0i is 3.141593 phase angle of -1.0-0.0i (the other side of the cut) is -3.141593
[edit] References
- C11 standard (ISO/IEC 9899:2011):
- 7.3.9.1 The carg functions (p: 196)
- 7.25 Type-generic math <tgmath.h> (p: 373-375)
- G.7 Type-generic math <tgmath.h> (p: 545)
- C99 standard (ISO/IEC 9899:1999):
- 7.3.9.1 The carg functions (p: 178)
- 7.22 Type-generic math <tgmath.h> (p: 335-337)
- G.7 Type-generic math <tgmath.h> (p: 480)
[edit] See also
C++ documentation for arg