C# – Why is double.NaN not equal to itself


Can someone explain this to me? In C# double.NaN is not equal to double.NaN

bool huh = double.NaN == double.NaN; // huh = false
bool huh2 = double.NaN >= 0; // huh2 = false
bool huh3 = double.NaN <= 0; // huh3 = false

What constant can I compare to a double.NaN and get true?

Best Solution

If you are curious, this is what Double.IsNaN looks like:

public static bool IsNaN(double d)
    return (d != d);

Funky, huh?