Uses for negative zero floating point value?

Question

Consider the following C++ code:

double someZero = 0;
std::cout << 0 - someZero << \'\\n\';   // prints 0
std::cout << -someZero << s         


        

Answer 1

I'm making a measuring app, and the -0 is very useful for mixed numbers (such as separating into feet and inches).

Imagine that we have a variable "length" that we're trying to separate into "feet" and "inches".

(This is java code, but the same idea is true for C++).

feet = Math.signum(length) * Math.floor(Math.abs(length / 12));
// could also do feet = length>0 ? Math.floor(length / 12) : Math.ceil(length / 12)
inches = Math.abs(length) % 12;

If the length is between -1 feet and 0 feet, we'd want it to say -0 for the feet so we know it's negative.