Division by Zero, Exception or Not?

[Sean Kirkpatrick]

Sometimes, when I think I understand something and try to explain it to
someone else, I realize that I don't understand it at all.

Consider:

Dim i As Integer
Dim d As Double
Dim a As Integer = 3
Dim b As Integer = 0

' case 1
Try
TextBox1.Text = a / b
Debug.WriteLine (i)
Catch ex As Exception
TextBox1.Text = "Uh Oh"
End Try

' case 2
Try
TextBox1.Text = a \ b
Debug.WriteLine (d)
Catch ex As Exception
TextBox1.Text = "Uh Oh"
End Try

' case 3
Try
i = a / b
Debug.WriteLine (i)
Catch ex As Exception
TextBox1.Text = "Uh Oh"
End Try

' case 4
Try
d = a \ b
Debug.WriteLine (d)
Catch ex As Exception
TextBox1.Text = "Uh Oh"
End Try

case 1 puts "Infinity" in TextBox1 but the other three throw an
exception and put "Uh Oh" there instead. This makes no sense to me. At
first thought, I would expect a div 0 error to ALWAYS result in an
exception as in 2, 3, and 4.

But then, maybe there's special behavior since VB "knows" that the
assignment is to a text box and so it gives a "friendly" answer for 1,
but why doesn't it do that for 2?

This seems VERY inconsistent behavior. If not, why?

Sean

[m.posseth]

Re: Division by Zero, Exception or Not?

Try to do the same thingy with option strict on and there is your answer :-)

regards

Michel Posseth



"Sean Kirkpatrick" <nannernanner@c ommunity.nospam > wrote in message
news:uZPe6gozFH A.3660@TK2MSFTN GP15.phx.gbl...[color=blue]
> Sometimes, when I think I understand something and try to explain it to
> someone else, I realize that I don't understand it at all.
>
> Consider:
>
> Dim i As Integer
> Dim d As Double
> Dim a As Integer = 3
> Dim b As Integer = 0
>
> ' case 1
> Try
> TextBox1.Text = a / b
> Debug.WriteLine (i)
> Catch ex As Exception
> TextBox1.Text = "Uh Oh"
> End Try
>
> ' case 2
> Try
> TextBox1.Text = a \ b
> Debug.WriteLine (d)
> Catch ex As Exception
> TextBox1.Text = "Uh Oh"
> End Try
>
> ' case 3
> Try
> i = a / b
> Debug.WriteLine (i)
> Catch ex As Exception
> TextBox1.Text = "Uh Oh"
> End Try
>
> ' case 4
> Try
> d = a \ b
> Debug.WriteLine (d)
> Catch ex As Exception
> TextBox1.Text = "Uh Oh"
> End Try
>
> case 1 puts "Infinity" in TextBox1 but the other three throw an exception
> and put "Uh Oh" there instead. This makes no sense to me. At first
> thought, I would expect a div 0 error to ALWAYS result in an exception as
> in 2, 3, and 4.
>
> But then, maybe there's special behavior since VB "knows" that the
> assignment is to a text box and so it gives a "friendly" answer for 1, but
> why doesn't it do that for 2?
>
> This seems VERY inconsistent behavior. If not, why?
>
> Sean[/color]

[Chris Dunaway]

Re: Division by Zero, Exception or Not?

Also look at the documentation for the DivideByZeroExc eption class

[alantolan@users.com]

Re: Division by Zero, Exception or Not?


You have the operators confused.

\ is the Integral division
/ the floating point


a / b, gives infinity
a \ b, gives a div-zero error


case 1

a / b -> Infiinty Infinity.ToStri ng() = "Infinity"


Case 2

a \ b DIVZERO


case 3

int i = a/b ; tryng to assign Infinity to integer - error


case 4

double d = a \b integral div by 0 error



NOTES:

You should turn on Option Strict
It will flag case 3 as an invalid assignment.


hth
Alan