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]

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

regards

Michel Posseth

"Sean Kirkpatrick" <na**********@community.nospam> wrote in message
news:uZ**************@TK2MSFTNGP15.phx.gbl...

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

[Chris Dunaway]

Also look at the documentation for the DivideByZeroException class

[alantolan]

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.ToString() = "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