question about returning value of a function

30 Dec 2006 3:28 PM

Bob

Hi,

i'm not sure to understand how a value is returned from a function.
Look at this code below about a simple function that compares a value with
values 1 from 5.
I thought: if the passed value (x = test(?)) is not from 1 to 5, then the
return = -1. That's ok.
If not, the function will return value z, but at the end of the for/next
loop, the other return (return -1) will also be executed, no? The line
'return -1' is outside of the loop and will be executed in all cases?

Thanks
Bob

Protected Sub Page_Load(ByVal sender As Object, ByVal e As System.EventArgs)
Handles Me.Load
        Dim x As Integer
        x = test(6)
        Response.Write(x)
    End Sub
    Function test(ByVal z As Integer) As Integer
        Dim i As Integer
        For i = 1 To 5
            If z = i Then
                Return z
            End If
        Next
        Return -1
    End Function

30 Dec 2006 3:44 PM

Just Me

For i = 1 To 5
            If z = i Then
                Return z
                Exit Function      '// ADD THIS LINE
            End If
        Next

Show quoteHide quote

"Bob" <.> wrote in message news:u6%23$dcCLHHA.3564@TK2MSFTNGP02.phx.gbl...
> Hi,
>
> i'm not sure to understand how a value is returned from a function.
> Look at this code below about a simple function that compares a value with
> values 1 from 5.
> I thought: if the passed value (x = test(?)) is not from 1 to 5, then the
> return = -1. That's ok.
> If not, the function will return value z, but at the end of the for/next
> loop, the other return (return -1) will also be executed, no? The line
> 'return -1' is outside of the loop and will be executed in all cases?
>
> Thanks
> Bob
>
>
> Protected Sub Page_Load(ByVal sender As Object, ByVal e As
> System.EventArgs) Handles Me.Load
>        Dim x As Integer
>        x = test(6)
>        Response.Write(x)
>    End Sub
>    Function test(ByVal z As Integer) As Integer
>        Dim i As Integer
>        For i = 1 To 5
>            If z = i Then
>                Return z
>            End If
>        Next
>        Return -1
>    End Function
>

30 Dec 2006 4:12 PM

Bob

Thanks, but in the code i used as example, there was no EXIT function. So
why will the Return -1 not be executed if the comparaison is true?

Show quoteHide quote

"Just Me" <news.microsoft.com> schreef in bericht
news:%2355rCmCLHHA.5104@TK2MSFTNGP06.phx.gbl...
>
>        For i = 1 To 5
>            If z = i Then
>                Return z
>                Exit Function      '// ADD THIS LINE
>            End If
>        Next
>
>
>
> "Bob" <.> wrote in message news:u6%23$dcCLHHA.3564@TK2MSFTNGP02.phx.gbl...
>> Hi,
>>
>> i'm not sure to understand how a value is returned from a function.
>> Look at this code below about a simple function that compares a value
>> with values 1 from 5.
>> I thought: if the passed value (x = test(?)) is not from 1 to 5, then the
>> return = -1. That's ok.
>> If not, the function will return value z, but at the end of the for/next
>> loop, the other return (return -1) will also be executed, no? The line
>> 'return -1' is outside of the loop and will be executed in all cases?
>>
>> Thanks
>> Bob
>>
>>
>> Protected Sub Page_Load(ByVal sender As Object, ByVal e As
>> System.EventArgs) Handles Me.Load
>>        Dim x As Integer
>>        x = test(6)
>>        Response.Write(x)
>>    End Sub
>>    Function test(ByVal z As Integer) As Integer
>>        Dim i As Integer
>>        For i = 1 To 5
>>            If z = i Then
>>                Return z
>>            End If
>>        Next
>>        Return -1
>>    End Function
>>
>
>

30 Dec 2006 4:32 PM

Herfried K. Wagner [MVP]

"Just Me" <news.microsoft.com> schrieb:
>        For i = 1 To 5
>            If z = i Then
>                Return z
>                Exit Function      '// ADD THIS LINE
>            End If
>        Next

This line will never be executed because the method will be leaved when
'Return z' is executed.

--
M S Herfried K. Wagner
M V P <URL:http://dotnet.mvps.org/>
V B <URL:http://dotnet.mvps.org/dotnet/faqs/>

30 Dec 2006 4:47 PM

Bob

Thanks

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"Herfried K. Wagner [MVP]" <hirf-spam-me-here@gmx.at> schreef in bericht
news:ugyTWADLHHA.1248@TK2MSFTNGP03.phx.gbl...
> "Just Me" <news.microsoft.com> schrieb:
>>        For i = 1 To 5
>>            If z = i Then
>>                Return z
>>                Exit Function      '// ADD THIS LINE
>>            End If
>>        Next
>
> This line will never be executed because the method will be leaved when
> 'Return z' is executed.
>
> --
> M S   Herfried K. Wagner
> M V P <URL:http://dotnet.mvps.org/>
> V B   <URL:http://dotnet.mvps.org/dotnet/faqs/>

30 Dec 2006 4:50 PM

Tom Leylan

The return statement is an instruction to "return" along with the value to
return so yes you will get a -1 in your test sample. The line Return -1 is
outside the loop but no it won't be executed in all cases. If the value
passed is between 1 and 5 the earlier return statement will exit the
function.

That said (if you're developing good habits) you should reduce the number of
return statements (ideally to one) and it should generally be at or near the
end of the function. This can be accomplished by assigning a return
variable (as needed in the routine) and returning it as the routine exits.

Show quoteHide quote

"Bob" <.> wrote in message news:u6%23$dcCLHHA.3564@TK2MSFTNGP02.phx.gbl...
> Hi,
>
> i'm not sure to understand how a value is returned from a function.
> Look at this code below about a simple function that compares a value with
> values 1 from 5.
> I thought: if the passed value (x = test(?)) is not from 1 to 5, then the
> return = -1. That's ok.
> If not, the function will return value z, but at the end of the for/next
> loop, the other return (return -1) will also be executed, no? The line
> 'return -1' is outside of the loop and will be executed in all cases?
>
> Thanks
> Bob
>
>
> Protected Sub Page_Load(ByVal sender As Object, ByVal e As
> System.EventArgs) Handles Me.Load
>        Dim x As Integer
>        x = test(6)
>        Response.Write(x)
>    End Sub
>    Function test(ByVal z As Integer) As Integer
>        Dim i As Integer
>        For i = 1 To 5
>            If z = i Then
>                Return z
>            End If
>        Next
>        Return -1
>    End Function
>