How to get a -0 result in floating point calculations and distinguish it from +0 in C#?

Question

The MSDN documentation mentions that double type includes negative zero. However, both -1.0 / double.PositiveInfinity and -double.Epsilon / 2

Answer 1

One way is to use the BitConverter.GetBytes. If you check the bytes, you will see that the sign bit for the value is actually set indicating that its negative.

byte[] zeroBytes = BitConverter.GetBytes(zero);
byte[] negZeroBytes = BitConverter.GetBytes(negZero);

bool sameBytes = zeroBytes[7] == negZeroBytes[7];