cabs

cabs

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Obtains the absolute value of a complex number

 #include <complex.h> double cabs ( double complex z  ); float cabsf ( float complex z  ); long double cabsl ( long double complex z  ); 

For a complex number z = x + y x i, where x and y are real numbers, cabs(z) is equal to the square root of x² + y², or hypot(x,y). The result is a non-negative real number.

Example

The absolute value of a complex number is its absolute distance from the origin in the complex planein other words, a positive real number, as this example demonstrates:

 double complex z[4]; z[0] = 3.0 + 4.0 * I; z[1] = conj( z[0] ); z[2] =  z[0] * I; z[3] = -( z[0] ); for (int i = 0; i < 4 ; i++ )   {     double a = creal(z[i]);     double b = cimag(z[i]);     printf ( "The absolute value of (%4.2f %+4.2f x I) is ", a, b );     double absolute_z = cabs(z[i]);     printf ( "%4.2f.\n", absolute_z );   } 

The output of the sample code is as follows:

 The absolute value of (3.00 +4.00 x I) is 5.00. The absolute value of (3.00 -4.00 x I) is 5.00. The absolute value of (-4.00 +3.00 x I) is 5.00. The absolute value of (-3.00 -4.00 x I) is 5.00. 

See Also

cimag( ), creal( ), carg( ), conj( ), cproj( )