C# Float to Double

static void Main(string[] args)
{
           double y = 23.12F;
           Console.Wri开发者_如何学PythonteLine(y);
           Console.Read();
}

why value of y shows 23.1200008392334 instead of 23.12

static void Main(string[] args)
    {
        int i = -9; uint j = (uint)i;
        Console.WriteLine(j);
        Console.Read();
    }

How j shows value 4294967287

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Floating points are only guaranteed to be exact for integer values; beyond that, they cannot represent all numbers; 23.1200008392334 is the closest it can get to 23.12, due to how IEEE754 works.

If you want "typical" handing of decimal values... use decimal instead:

decimal y = 23.12M;

With the uint - because uint doesn't have negative values. Instead, you are tracking backwards from the maximum value of uint. If you don't want this, use checked:

uint j = checked((uint) i);

or

checked
{
    uint j = (uint)i;
}

then it will explode in a shower of sparks instead. Sometimes a good thing; sometimes bad. unchecked is the default.

---

According to MSDN 'that's just how double works' http://social.msdn.microsoft.com/forums/en-US/csharpgeneral/thread/1fcf6486-807d-4dce-8aef-7fe5268b568d/

I know that this is Java, but very similar to C# : Convert float to double without losing precision