cargf, carg, cargl - cppreference.com (original) (raw)

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.

  1. 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

[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

#include <stdio.h> #include <complex.h>   int main(void) { double complex z1 = 1.0+0.0I; printf("phase angle of %.1f%+.1fi is %f\n", creal(z1), cimag(z1), carg(z1));   double complex z2 = 0.0+1.0I; 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

[edit] See also