Question

How do I perform a twos complement on a double and return a double?

Answer 1

If you are trying to do the two’s complement of the internal bit representation of the double, you can use the BitConverter class.

Something like:

double x = 12345.6;
Int64 bits = BitConverter.DoubleToInt64Bits(x);
bits = ~bits + 1;
x = BitConverter.Int64BitsToDouble(bits);

I’m not sure why you would want to do this, though…