Public Function PPF(Cost As Double, Price As Double) As String
Dim x As Long
'Dim x As Double

x = Round((1 - (Cost / Price)) * 100, 0)

Select Case x

Case 45 To 49.99
PPF = "45"

Case 50 To 54.99
PPF = "50"

Case Else
PPF = "DEFAULT"

End Select

End Function


Declaring x as long if I pass Cost/Price values of 4.05/8.10 then PPF
returns "45". If I declare x as Double then PPF returns "50".

In both cases x displays a value of 50 in the locals window.

I don't understand why this happens.

On Wed, 7 Sep 2011 13:37:17 -0700 (PDT), "Steve P."
<x (AT) monkeybutler (DOT) com> wrote:

Which includes >49.99 to <50.

Rounding. The values can not be represented exactly in floating
point. In the case of double, the rounding just happens to go in the
direction you are expecting.

Sincerely,

Gene Wirchenko

On Sep 7, 5:43*pm, Gene Wirchenko <ge... (AT) ocis (DOT) net> wrote:
Thanks for the reply. I did a little research on floating point and
while I can't say that I fully understand exactly what is happening at
least I can accept that it is possible.

On Thu, 8 Sep 2011 06:49:46 -0700 (PDT), "Steve P."
<x (AT) monkeybutler (DOT) com> wrote:

[snip]

It has to do with how the number is represented in binary.
One-third can not be represented exactly in decimal. Similarly,
one-tenth and one-hundredth can not be represented exactly in binary.

One way to avoid the problem (or much of it) is to deal with a
decimal type or to represent the dollar values in pennies.

Sincerely,

Gene Wirchenko