long integers division close to whole number rounds up instead of down with Math.Floor()

[BadButBit]

I have a filing system that divides my massive file into a series of smaller files, opens the FileStream and positions it at a location relative to the intIndex_Revised(times record size). All records are indexed and all works well. But at a large number like the one below, where the value inside the Math.Floor() should be 33.9999999 its output is 34 which then gives me an inIndex_Revised (for the 35th file stream counting zero) of -1 (times intRecordSize) which crashes my system.


public static int intCW_LL_NumRecPerFile = (int)Math.Pow(2, 19);

public static classFileStreamManager CW_LL_Rec_FileStream_Get(long index)
{
index = 17825791;
classFileStreamManager cFS = null;
int intFileNumber = (int)Math.Floor( (float) ((double)index / (double)intCW_LL_NumRecPerFile));
int intIndex_Revised = (int)((long)index - (long)intFileNumber * (long)intCW_LL_NumRecPerFile);
...

}


the division inside the Math.Floor() was originally

int intFileNumber = (int)Math.Floor((float)index/(float)intCW_LL_NumRecPerFile));

but I changed it when i ran was watching it through the Debugger to catch where it crashed. It doesn't fix the problem so I added the following lines to catch and correct it.

if (intIndex_Revised < 0)
{
intFileNumber--;
intIndex_Revised = (int)((long)index - (long)intFileNumber * (long)intCW_LL_NumRecPerFile);
if (intIndex_Revised > intCW_LL_NumRecPerFile)
{
System.Windows.Forms.MessageBox.Show("Error calculating CW__LL_REc_Filestream_Gret()");
}
}

This works(for now) but is there a better way?

BadButBit





my code is perfect until i don't find a bug

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