find first non-zero digit after decimal point using VB.net

Question

I'm working to find the position of the first none-zero digit after the decimal point

So far I have managed to find the number of decimal digits using

Dim value As Single = 2.0533
Dim numberOfdecimaldigits As Integer = value.ToString().Substring(value.ToString().IndexOf(".") + 1).Length
MessageBox.Show(numberOfdecimaldigits)

if I have 4.0342, then I'm looking to get 2 for the position of 3 after the decimal value. What I want to do with this data, is to add 2 to the whole number depending on the location of the none-zero digit. For example: for 4.0342, I want the system to add 0.02 to it. If it's 5.00784, then I want to add 0.002 to it.

Is there a way to know the position of first none-zero digit after the decimal point?

Thank you in advance

score 2 · Accepted Answer · answered May 10 '16 at 14:17

2

I strongly recommend not using strings here — you are performing a numerical algorithm, it’s more direct and more efficient to work on the number using numeric logic:

value = value - Math.Floor(value) ' Get rid of integer digits
Dim position = 0

While value > 0 AndAlso Math.Floor(value) = 0
    value = value * 10
    position += 1
End While

If value = 0 Then Throw New Exception(…)
Return position

answered May 10 '16 at 14:17

Konrad Rudolph

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I just have one more question. I use this Dim a As Single = 7245.00758 MessageBox.Show(a) and when I see the message it says 7245.008. Why is it not 7245.00758? Thank You – Satvir Singh May 10 '16 at 15:07
@SatvirSingh That’s normal. The reason is here: http://stackoverflow.com/q/588004/1968 – Konrad Rudolph May 10 '16 at 15:32
Thank you for link it explained the information really well – Satvir Singh May 11 '16 at 08:49

score 0 · Answer 2 · answered Sep 17 '20 at 18:59

Here is my take on the matter which prevents an infinite loop

value = value - Math.Floor(value) ' Get rid of integer digits

If value = 0 Then Throw New Exception(...)

value = 1/value ' Invert the value
Dim position = 0

While value > 1
    value = value / 10
    position += 1
End While

Return position

find first non-zero digit after decimal point using VB.net

2 Answers2