cabsf, cabs, cabsl

 

C

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Technical Specifications

 

Numerics

Common mathematical functions

Floating-point environment

Complex number arithmetics

Random number generation

Type-generic math

 

Complex number arithmetic

Types and the imaginary constant
complex _Complex_I CMPLX	imaginary _Imaginary_I I
Manipulation
cimag creal carg	cabs conj cproj
Power and exponential functions
cexp clog	cpow csqrt
Trigonometric functions
ccos csin ctan	cacos casin catan
Hyperbolic functions
ccosh csinh ctanh	cacosh casinh catanh

 

Defined in header <complex.h>
float       cabsf( float complex z );	(1)	(since C99)
double      cabs( double complex z );	(2)	(since C99)
long double cabsl( long double complex z );	(3)	(since C99)
Defined in header <tgmath.h>
#define fabs( z )	(4)	(since C99)

1-3) Computes the complex absolute value (also known as norm, modulus, or magnitude) of z.

4) Type-generic macro: if z has type long double complex or long double imaginary, cabsl is called. If z has type float complex or float imaginary, cabsf is called. If z has type double complex or double imaginary, cabs is called. For real and integer types, the corresponding version of fabs is called.

Parameters

z

-

complex argument

Return value

If no errors occur, returns the absolute value (norm, magnitude) of z.

Errors and special cases are handled as if the function is implemented as hypot(creal(z), cimag(z))

Example

Run this code

#include <stdio.h>
#include <complex.h>
 
int main(void)
{
    double complex z = 1.0 + 1.0*I;
    printf("%.1f%+.1fi cartesian is rho=%f theta=%f polar\n",
           creal(z), cimag(z), cabs(z), carg(z));
}

Output:

1.0+1.0i cartesian is rho=1.414214 theta=0.785398 polar

References

• C11 standard (ISO/IEC 9899:2011):

• 7.3.8.1 The cabs functions (p: 195)

• 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):

• 7.3.8.1 The cabs functions (p: 177)

• 7.22 Type-generic math <tgmath.h> (p: 335-337)

• G.7 Type-generic math <tgmath.h> (p: 480)

See also

cargcargfcargl (C99)(C99)(C99)	computes the phase angle of a complex number (function)
abslabsllabs (C99)	computes absolute value of an integral value (|x|) (function)
fabsfabsffabsl (C99)(C99)	computes absolute value of a floating-point value (|x|) (function)
hypothypotfhypotl (C99)(C99)(C99)	computes square root of the sum of the squares of two given numbers (√x2 +y2 ) (function)
C++ documentation for abs