[RESOLVED] Trouble with code to round down a number

[FSPH]

Hi there,

I obtained code to round down a number to a second non-zero digit. Unfortunately, it doesn't work properly. When dblX is 82.02, I would like to round down this number to 82. Would you have any idea how to modify the code so that I works properly?

Thanks for your help!


Public Function RoundDown2ndDigit(ByVal dblX As Double, Optional ByVal dblStep As Double) As Double
Dim strE As String, dblM As Double

strE = Format(Abs(dblX), "0.0E+0")
dblStep = CDbl("0.1E" & Mid(strE, 5))
dblM = CDbl(strE)
If dblM > Abs(dblX) Then dblM = dblM + dblStep
RoundDown2ndDigit = (Sgn(dblX) * dblM)

End Function

[Code Doc]

Private Sub Form_Load()
Dim MyNum As Single
MyNum = 82.02
MsgBox "My number rounded down is " & Int(MyNum)
End Sub

[anhn]

Not sure whether I understand your question on "second non-zero digit".
Try this:

Public Function RoundDown2ndDigit(ByVal x As Double) As Double
   Dim n As Long
   
   n = Int(Log(Abs(x)) / Log(10)) - 1
   RoundDown2ndDigit = Fix(x / 10 ^ n) * 10 ^ n
End Function

That will round
82.02 to 82
8.35 to 8.3
123.56 to 120
-0.0345 to -0.034

Instead of using Log(), you also can use:

   Dim s1 As String
   
   s1 = Format(x, "Scientific")
   n = CLng(Mid$(s1, InStr(s1, "E") + 1)) - 1

[Code Doc]

AnHn said, "Not sure whether I understand your question on "second non-zero digit".
------------
Agreed. OP, please be more definitive.

[Bruce Fox]

In other words, the poster wants to round from 2 decimal places. Well that’s my interpretation

This is a zero second digit: 82.00 (of course you would represent this as 82, hence the inference on the non zero)
This is a non zero second digit: 82.02

[FSPH]

Hello,

anhn - thanks very much for the code, it works.

Bruce Fox - thanks for the clarification that I should have put in.