ASP.Net conversion on using float numbers

I have a conversion or some kind of type casting problem in my asp.net/C# math app. A contractor wrote some code to calculate a relative standard error in an assembly. But when I run it, apparently doesn't work right.

The data types are as follows:

        public double dSwx = 0.0, dSw = 100.0;
        public double dTx = 0.0, dTwn=0.0;
        public float fEstimateVal = 0.0F;       //  For Estimate Value, it should be same as Swx/Sw

        //i did a system.out on this in my web app and they came out as:
        //zeroDataCell.dSwx = 0.0;
        //zeroDataCell.dSw = 100.0;

        zeroDataCell.fEstimateVal = (float)(zeroDataCell.dSwx / zeroDataCell.dSw) * 100.0f;

       //so now zeroDataCell.fEstimateVal should be 0.0, but my code blows 
       //throug开发者_StackOverflow社区h the if statement below, is there some conversion problem? 
       //should i use EqualsTo?            


        if (zeroDataCell.fEstimateVal != 0.0f)
            zeroDataCell.fRse = zeroDataCell.fTwx / zeroDataCell.fEstimateVal * 100.0f;0

Why does fEstimateVal that eqauls zero stil run through the if loop?

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Dealing with float/double numbers is always precision balancing. If you want to compare it against clear 0, convert it to integer and compare after.

Or add some precisio stuff like

((int)(floatnumber * 100)) == 0.

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The following code works fine here:

if (zeroDataCell.fEstimateVal != 0)
  zeroDataCell.fRse = zeroDataCell.fTwx / zeroDataCell.fEstimateVal * 100.0f;