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Calculates the absolute value of a complex number.

double _cabs( 
   struct _complex z 


Complex number.

Return Value

_cabs returns the absolute value of its argument if successful. On overflow, _cabs returns HUGE_VAL and sets errno to ERANGE. You can change error handling with _matherr.


The _cabs function calculates the absolute value of a complex number, which must be a structure of type _complex. The structure z is composed of a real component x and an imaginary component y. A call to _cabs produces a value equivalent to that of the expression sqrt( z.x*z.x + z.y*z.y ).


Routine Required header Compatibility
_cabs <math.h> Win 98, Win Me, Win NT, Win 2000, Win XP

For additional compatibility information, see Compatibility in the Introduction.


All versions of the C run-time libraries.


// crt_cabs.c
/* Using _cabs, this program calculates
 * the absolute value of a complex number.
#include <math.h>
#include <stdio.h>

int main( void )
   struct _complex number = { 3.0, 4.0 };
   double d;

   d = _cabs( number );
   printf( "The absolute value of %f + %fi is %f\n",
           number.x, number.y, d );


The absolute value of 3.000000 + 4.000000i is 5.000000

See Also

Floating-Point Support Routines | abs | fabs | labs | Run-Time Routines and .NET Framework Equivalents