Why is double.NaN not equal to itself?

Question

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 >=          


        

Answer 1

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

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

Funky, huh?