{{keywords>wiki library source code example reference}}
===== fabs =====
<code c>
    double fabs(double);
</code>
calculates the absolute number of a given value

===== C Sourcecode Example =====
compile in linux with: gcc fabs.c -o fabs **-lm** -Wall
<code c>     
#include <stdio.h> /* including standard library */
//#include <windows.h> /* uncomment this for Windows */

#include <math.h> /* including math library */

int main ( void ) 
{
double y,x;
x = 4.2422;
y = -3284.2;
printf("the fabs of 4.2422 is %f\n", fabs(x) );
printf("and the fabs of -3284.2 is %f\n ", fabs(y) );
return 0;
}

</code>

==== output ====
   output:
   user@host:~$ ./fabs 
   the fabs of 4.2422 is 4.242200
   and the fabs of -3284.2 is 3284.200000