The GNU C Library - Absolute Value

Absolute Value

These functions are provided for obtaining the absolute value (or magnitude) of a number. The absolute value of a real number x is x is x is positive, -x if x is negative. For a complex number z, whose real part is x and whose imaginary part is y, the absolute value is sqrt (x*x + y*y) .

Prototypes for abs and labs are in `stdlib.h'; fabs and cabs are declared in `math.h'.

Function int abs (int number)

This function returns the absolute value of number.

Most computers use a two's complement integer representation, in which the absolute value of INT_MIN (the smallest possible int ) cannot be represented; thus, abs (INT_MIN) is not defined.

Function long int labs (long int number)

This is similar to abs , except that both the argument and result are of type long int rather than int .

Function double fabs (double number)

This function returns the absolute value of the floating-point number number.

Function double cabs (struct { double real, imag; } z)

The cabs function returns the absolute value of the complex number z, whose real part is z.real and whose imaginary part is z.imag . (See also the function hypot in Exponents and Logarithms.) The value is:

	sqrt (z.real*z.real + z.imag*z.imag)