Absolute value without sign *Resolved*

[swatty]

Is there a way in C++ to get the absolute value of an integer ??


if after a calculation i get a value returned -2 how can i use some function to get 2

I don't want to write

if(c<0) c = c -c -c ; 

[HairyDave]

abs(value)

Don't know if there are any float/double etc methods for this - probably, but abs is the right one for ints.

Need math.h I think for this.

HD

[parksie]

In C++, it's the <cmath> header

You can use fabs() for floating-point numbers.

[swatty]

Thank should have tried it first.

[jim mcnamara]

There are a lot of 'abs' functions - cabs(), labs(), etc.

The generally accepted dogma is that you should use a macro for functions like sgn(), abs(), etc because they are faster - a lot faster.

Kinda like this:

#define abs(c)  ( (c<0) ? (-1)*c : c )

You can also force 'inlining' by using macros -
This does a complex reciprocal for instance.
arg & out are type Complex (a struct)

#define LCMPLXrecip(arg,out)	\
{ long denom; denom = lsqr((arg).x) + lsqr((arg).y);\
if(denom==0L) overflow=1; else {(out).x = divide((arg).x,denom,bitshift);\
(out).y = -divide((arg).y,denom,bitshift);}}