on 8/30/01 6:12 AM, Francois Van Lerberghe at fvanlerberghe /AT/ freegates .DOT be
wrote:
> I see some strange behavior with VFloat field :
>
> I store -18592.01 in it (with SetString or Value, no matter)
> When I get the value, I see different values in the EditField with
> GetString and Value :
>
> FloatField.GetString -> -18592 (same in VApp)
> FloatField.Value -> -18592.0097656
>
> With the value 12394.68, I get :
>
> FloatField.GetString -> 12394.7 (same in VApp)
> FloatField.Value -> 12394.6796875
>
> Using VDouble, I get the same value that I store.
Maybe in the examples you looked at; however, there will be others where
this is not the case.
>
> 1/ Is there
> - a mathematical issue
> - a Valentina issue
> - a RealBasic issue
Sort of all three. Basically the problem is representation of decimal
numbers within the computer. Certain fractional forms are not precisely
representable as a number.
>
> 2/ Must I use VDouble field in order to retrieve safely the value I
> stored ?
> (I need 2 decimals precision because it's for storing money amount)
As noted above, using vDouble will not resolve your problem.
Store the money values as a string with two-decimals. Define a virtual
method which converts that to a number; this can be used for sorting/find
operations if needed. The string field can be brought into RB very easily
and with no time penalty. Use the format function with a format
specification "#.00" or "#,00" as needed.
Best regards,
John Roberts
mailto:jarobe01@athena.louisville.edu
©2001 john roberts |
