signum
Returns the sign of a double value.
-0.0 if the value is considered zero and negatively signed,
+0.0 if the value is considered zero and positively signed,
-1.0 if the value is considered less than zero,
+1.0 if the value is considered greater than zero.
Return
-1.0 if a is negative, 0.0 if a is zero, and 1.0 if a is positive.
Parameters
a
The double value to check.