Decimal precision in VBA macro

[FredM400]

I need some help with number precision and Variant data types.

vIdx in defined as Integer and used as a array index

I have 3 variables, all defined as Variants:
vBaseCellValue(vIdx)
vCompCellValue(vIdx)
vCellVariance

I have the statement;

vCellVariance = vBaseCellValue(vIdx) - vCompCellValue(vIdx)

Under the conditions
vBaseCellValue(vIdx) = 29435.15
vCompCellValue(vIdx) = 29435.15

I would expect the variable vCellVariance to be equal to zero.

The debug Immediate window say the variable vCellVariance is actual equal to 7.275958E-12.
A really really small number, but not zero.

My compare to zero fails and the program goes off down the wrong path.


How can I the correct answer of Zero????

 

[Seti]

A brute force way would be to use:

vCellVariance = ROUND(vBaseCellValue(vIdx) - vCompCellValue(vIdx),2)