分割双倍时C＃精度损失

Question

The function bellow is passed a string "1004233" and prints the following output:
D1 = 1.004233
D2 = 0.00423299999999993
D3 = 4232.99999999993
D4 = 4232

I need D4 to print 4233 and not 4232. How do i stop this precision loss from happening?

public string someFunc(String s){
        string retval = "0";
        try{
            int id = int.Parse(s);
            double d = (double)id / (double)1000000;
            Console.WriteLine("D1 = " + d);
            d = d - Math.Truncate(d);
            Console.WriteLine("D2 = " + d);
            d = d * (double)1000000;
            Console.WriteLine("D3 = " + d);
            retval = "" + Math.Truncate(d);
            Console.WriteLine("D4 = " + retval);
        }catch(Exception ex){}
        return retval;
}

Answer 1

This is the standard floating-point question .

Use a decimal instead.
Although decimal s also don't have infinite precision, they are implemented in base 10, so they will give you the results you expect.

Answer 2

Use decimal arithmetic instead of floating-point (double). More information to be found:

• http://gregs-blog.com/2007/12/10/dot-net-decimal-type-vs-float-type/