Rounding Numbers

ricespn · November 6th, 2006, 01:00 PM

Hi,

How can i round a decimal number to the next number?

Example:

2.45 = 3
.01 = 1
34.01 = 35

Thanks !

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Strange and crazy, but everything is possible

woodyz · November 6th, 2006, 03:19 PM

A complex subject.
There are numerous ways to approach rounding: You have to take into consideration such things as Bankers Rounding, and the various default roundings applied by intrinsic vb functions.

Here is a little code that hopefully does what you wnnt:

Code:

Private Sub Command1_Click()


    Dim dblPlaces As Double
    Dim dblAmount As Double
    Dim dblRounded As Double

    dblAmount = 34.01

    ' dblPlaces is the decimal place you want to round to:
    '    1 = no decimal places
    '    10 = 1 decimal place
    '    100 = 2 decmial places... and so on
    dblPlaces = 1

    dblRounded = Fix(dblAmount * dblPlaces) / dblPlaces
    ' The following needs to be done for positive amounts, but not
    '   for negative amounts for true "rounding up" functionality
    '   so you would need to add a test for negative amounts and NOT
    '   do this for negatives.
    dblRounded = dblRounded + (1 / dblPlaces)  ' See note below

    Debug.Print dblRounded

End Sub

Note the line of code that moves the value up for positive numbers. You don't do this for the negative numbers as you'll move one value unit too far. Also remember that rounding up for negative numbers moves you towards zero. If you always want to move "away" from zero, then you have to apply the ABS function to your calculations and then re-apply the sign after the rounding operation is complete.

Make sense?

Have fun...

Woody Z http://www.learntoprogramnow.com

marcostraf · November 6th, 2006, 03:33 PM

I guess the number 1.0 should remain 1.0 and not 2.0, right?
Code non tested:

public function Ceil(byval n as double) as double
if n-fix(n) = 0 then
ceil= n '' if the decimal part is zero, no change
else
ceil = fix(n)+1 '' add 1 to the inetger part
end function

ricespn · November 6th, 2006, 05:00 PM

Thanks guys!

But:

What about this one:

Private Sub Command1_Click()

    Dim dblAmount As Double

    dblAmount = .1
    Var = Int(dblAmount)
    If Var = 0 Then
    Var = Var + 1
    End If

   Debug.Print Var

End Sub

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Strange and crazy, but everything is possible

woodyz · November 6th, 2006, 05:19 PM

Quote:

quote:Originally posted by ricespn
Thanks guys!

But:

What about this one:

Private Sub Command1_Click()

    Dim dblAmount As Double

    dblAmount = .1
    Var = Int(dblAmount)
    If Var = 0 Then
    Var = Var + 1
    End If

Debug.Print Var

End Sub

I don't think that will do what you want, which is rounding up. In your code, you round up ONLY if the value is zero after rounding - which has several problems with it, including that if your value was zero to start with, it would result in a value of one!!!

Take another look at the fix I suggested. Or better still, take a look at http://www.xbeat.net/vbspeed/c_Round.htm.

I have written a great deal of rounding algorithms since I've done a lot of work in the financial arena - and there is a lot to understand about how all this works if you need dependable results.

Woody Z http://www.learntoprogramnow.com

ricespn · November 6th, 2006, 05:24 PM

You are right! I found that out after I posted it

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Strange and crazy, but everything is possible