6.2.15 carg Function

Calculates the argument of a double precision complex value.

Include

<complex.h>

Prototype

double complex carg(double complex z);

Argument

z

value for which to return the argument

Return Value

Returns the argument (or phase angle) of z in the interval $\mathrm{[-\pi ,\; +\pi ]}$ and with a branch cut along the negative real axis.

Example

See the notes at the beginning of this chapter or section for information on using printf() or scanf() (and other functions reading and writing the stdin or stdout streams) in the example code.

#include <stdio.h>
#include <complex.h>

int main(void)
{
  double complex x, y;

  x = -2.0 + 1.0*I;
  y = carg(x);
  printf("The complex argument of %f + %fi is %f + %fi\n", creal(x), cimag(x), creal(y), cimag(y));
}

Example Output

The complex argument of -2.000000 + 1.000000i is 2.677945 + 0.000000i