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| Author |
Question about Long calculation
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| Michael Bosco 2004-11-26, 8:55 pm |
| Hi. I'm seeing some weird behavior when doing a simple calculation in
VB6. I have a Long defined like so...
Dim lngNumber As Long
This line works fine...
lngNumber = 56000
However, this line gives me an overfow error...
lngNumber = (56 * 1000)
How is the second line different from the first??
Thanks.
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| Rick Rothstein 2004-11-26, 8:55 pm |
| > Hi. I'm seeing some weird behavior when doing a simple calculation in
> VB6. I have a Long defined like so...
> Dim lngNumber As Long
>
> This line works fine...
> lngNumber = 56000
>
> However, this line gives me an overfow error...
> lngNumber = (56 * 1000)
>
> How is the second line different from the first??
VB has what I consider a strange quirk (a bug in my opinion)... for
non-floating point multiplication, VB uses the smallest memory size it
can get away with. It determines this by looking at the size of the
numbers it is going to multiply together and (here is the part I think
is buggy) not by looking at the size of the variable the answer will be
stored in. Since 56 and 1000 will BOTH fit into an Integer sized memory
area, VB attempts to store the answer in an Integer sized memory area
(paying no attention to the data type of the lngNumber variable). But
the product, 56000, is too large to fit and so VB throws an error.
However, if you force one (or both) of these to numbers to a Long
(either by tacking on the ampersand (&) suffix or by using the CLng
function), then the calculation would work. Either...
lngNumber = 56& * 1000
or
lngNumber = CLng(56) * 1000
Rick - MVP
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| Gerald Hernandez 2004-11-26, 8:55 pm |
| VB's default casting of 56 and 1000 are Integer (Int16).
You need to tell VB that these should be treated as Longs (Int32)
You can do this by appending the Long datatype decorator & like so:
lntNumber = (56& * 1000&)
Gerald
"Michael Bosco" <mbosco51@hotmail.com> wrote in message
news:f1ba6018.0411261241.14dc16a2@posting.google.com...
> Hi. I'm seeing some weird behavior when doing a simple calculation in
> VB6. I have a Long defined like so...
> Dim lngNumber As Long
>
> This line works fine...
> lngNumber = 56000
>
> However, this line gives me an overfow error...
> lngNumber = (56 * 1000)
>
> How is the second line different from the first??
>
> Thanks.
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