/* en C */

#include <stdio.h>
#include <math.h>

#define ABS(x) ((x) > 0 ? (x) : -(x))

int main(void)
{
 double x = -9.0;
 double y = sqrt(ABS(x));

 printf("sqrt(ABS(%f))=%f\n",x,y);

 return 0;
}