Calculates the positive difference between two arguments.
double fdim(double d1, double d2);
float fdimf(float d1, float d2);
long double fdiml(long double d1, long double d2);
d1, d2 Values of which difference is to be computed (|d1 - d2|)
Normal: Positive difference between two arguments
Abnormal: Range error: HUGE_VAL, HUGE_VALF, or HUGE_VALL