sentinel controlled loop, string comparison

[David]

As part of a project I would like to be able to control when inputting names
is completed by using a
sentinel controlled loop. The control for the loop is to continue entering
names until a "-1" is encountered.

First time through the loop

Private Sub cmdName_Click()
Dim LName(20) As String, FName(20) As String
Dim Number As Integer
Number = 0
' Use sentinel-controlled program to control entering names
lstStudents.Clear
lstStudents.AddItem "Last Name" & vbTab & "First Name"
LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
FName(Number) = InputBox("Enter First Name;", "VBHTP")
Do Until LName(Number) = -1
Number = Number + 1
LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
FName(Number) = InputBox("Enter First Name;", "VBHTP")
Loop
End Sub

At the Statement with the comparison to -1, I get a type mismatch error on
execution.

Does VB allow a comparion of a string variable (in an array) to an integer
or does either the string variable
or integer have to be changed to make the comparison?

any help or comments or suggestions would be appreciated. Also, this method
seems cumbersome,
any suggestions to something a little more elegant

Thanks ahead of time.

David

[Jim Edgar]

David --

Instead of
> Do Until LName(Number) = -1

try

Do Until LName(Number) = "-1"

Hope it helps

Jim Edgar

[Rick Rothstein]

Consider these changes to your code:

Private Sub cmdName_Click()
Dim LName(20) As String, FName(20) As String
Dim Number As Integer
Number = -1
lstStudents.Clear
lstStudents.AddItem "Last Name" & vbTab & "First Name"
Do
Number = Number + 1
LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
If LName(Number) <> "-1" Then
FName(Number) = InputBox("Enter First Name;", "VBHTP")
End If
Loop While LName(Number) <> "-1"
End Sub

See if you can figure out what I did and why I did it. Also, you might want
to consider a test statement to make sure your user doesn't try and enter a
22nd (element #21) line. You might also want to consider adding the items to
the ListBox as they are typed in so the user will know that his entry wasn't
ignored.

Rick


"David" <shefchem@swbell.net> wrote in message
news:38f2586c$1@news.devx.com...
>
> As part of a project I would like to be able to control when inputting
names
> is completed by using a
> sentinel controlled loop. The control for the loop is to continue
entering
> names until a "-1" is encountered.
>
> First time through the loop
>
> Private Sub cmdName_Click()
> Dim LName(20) As String, FName(20) As String
> Dim Number As Integer
> Number = 0
> ' Use sentinel-controlled program to control entering names
> lstStudents.Clear
> lstStudents.AddItem "Last Name" & vbTab & "First Name"
> LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
> FName(Number) = InputBox("Enter First Name;", "VBHTP")
> Do Until LName(Number) = -1
> Number = Number + 1
> LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
> FName(Number) = InputBox("Enter First Name;", "VBHTP")
> Loop
> End Sub
>
> At the Statement with the comparison to -1, I get a type mismatch error on
> execution.
>
> Does VB allow a comparion of a string variable (in an array) to an integer
> or does either the string variable
> or integer have to be changed to make the comparison?
>
> any help or comments or suggestions would be appreciated. Also, this
method
> seems cumbersome,
> any suggestions to something a little more elegant
>
> Thanks ahead of time.
>
> David

[Bill McCarthy]

David,

Rick's code should work, but I can't help wondering if something other
than -1 is more suitable to end the loop. Say if you changed the title to
"Enter in New Last Name" or similar, you could detect if the hit "Esc" or
Cancel by checking the strptr of the return string.
eg:
If strPtr(FName(Number)) Then 'did not press cancel
If Len(FName(Number)) Then 'they typed something





"Rick Rothstein" <rick_newsgroup@email.com> wrote in message
news:38f2b85f$1@news.devx.com...
> Consider these changes to your code:
>
> Private Sub cmdName_Click()
> Dim LName(20) As String, FName(20) As String
> Dim Number As Integer
> Number = -1
> lstStudents.Clear
> lstStudents.AddItem "Last Name" & vbTab & "First Name"
> Do
> Number = Number + 1
> LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
> If LName(Number) <> "-1" Then
> FName(Number) = InputBox("Enter First Name;", "VBHTP")
> End If
> Loop While LName(Number) <> "-1"
> End Sub
>
> See if you can figure out what I did and why I did it. Also, you might
want
> to consider a test statement to make sure your user doesn't try and enter
a
> 22nd (element #21) line. You might also want to consider adding the items
to
> the ListBox as they are typed in so the user will know that his entry
wasn't
> ignored.
>
> Rick
>
>
> "David" <shefchem@swbell.net> wrote in message
> news:38f2586c$1@news.devx.com...
> >
> > As part of a project I would like to be able to control when inputting
> names
> > is completed by using a
> > sentinel controlled loop. The control for the loop is to continue
> entering
> > names until a "-1" is encountered.
> >
> > First time through the loop
> >
> > Private Sub cmdName_Click()
> > Dim LName(20) As String, FName(20) As String
> > Dim Number As Integer
> > Number = 0
> > ' Use sentinel-controlled program to control entering names
> > lstStudents.Clear
> > lstStudents.AddItem "Last Name" & vbTab & "First Name"
> > LName(Number) = InputBox("Enter Last Name; -1 to end",
"VBHTP")
> > FName(Number) = InputBox("Enter First Name;", "VBHTP")
> > Do Until LName(Number) = -1
> > Number = Number + 1
> > LName(Number) = InputBox("Enter Last Name; -1 to end",
"VBHTP")
> > FName(Number) = InputBox("Enter First Name;", "VBHTP")
> > Loop
> > End Sub
> >
> > At the Statement with the comparison to -1, I get a type mismatch error
on
> > execution.
> >
> > Does VB allow a comparion of a string variable (in an array) to an
integer
> > or does either the string variable
> > or integer have to be changed to make the comparison?
> >
> > any help or comments or suggestions would be appreciated. Also, this
> method
> > seems cumbersome,
> > any suggestions to something a little more elegant
> >
> > Thanks ahead of time.
> >
> > David
>
>

[Rick Rothstein]

I wasn't sure how far to take my answer. Personally, I don't like popping
InputBox's in my user's face, one after the other, like that. Because this
is a "getting started" newsgroup, I figured David will "grow" through the
various GUI presentation stages that we all(?) did. Hence, I thought I would
restrict my post to an improvement, code-wise, for David to consider (within
the GUI he had created).

Your suggestion is, of course, valid. I hope the undocumented "strPtr"
function doesn't throw him though. In addition, we both forgot to suggest to
David that he should consider what he wants to do if his user simply hits
the Enter key without typing in any text at all. For the interface method
David is using, he could probably omit the strPtr function that you
suggested altogether and simply end the loop when a (Trim'ed) blank entry is
inputted.

Rick


"Bill McCarthy" <billmcc@gsat.edu.au> wrote in message
news:38f2f7d1@news.devx.com...
> David,
>
> Rick's code should work, but I can't help wondering if something other
> than -1 is more suitable to end the loop. Say if you changed the title to
> "Enter in New Last Name" or similar, you could detect if the hit "Esc" or
> Cancel by checking the strptr of the return string.
> eg:
> If strPtr(FName(Number)) Then 'did not press cancel
> If Len(FName(Number)) Then 'they typed something
>
>
>
>
>
> "Rick Rothstein" <rick_newsgroup@email.com> wrote in message
> news:38f2b85f$1@news.devx.com...
> > Consider these changes to your code:
> >
> > Private Sub cmdName_Click()
> > Dim LName(20) As String, FName(20) As String
> > Dim Number As Integer
> > Number = -1
> > lstStudents.Clear
> > lstStudents.AddItem "Last Name" & vbTab & "First Name"
> > Do
> > Number = Number + 1
> > LName(Number) = InputBox("Enter Last Name; -1 to end", "VBHTP")
> > If LName(Number) <> "-1" Then
> > FName(Number) = InputBox("Enter First Name;", "VBHTP")
> > End If
> > Loop While LName(Number) <> "-1"
> > End Sub
> >
> > See if you can figure out what I did and why I did it. Also, you might
> want
> > to consider a test statement to make sure your user doesn't try and
enter
> a
> > 22nd (element #21) line. You might also want to consider adding the
items
> to
> > the ListBox as they are typed in so the user will know that his entry
> wasn't
> > ignored.
> >
> > Rick
> >
> >
> > "David" <shefchem@swbell.net> wrote in message
> > news:38f2586c$1@news.devx.com...
> > >
> > > As part of a project I would like to be able to control when inputting
> > names
> > > is completed by using a
> > > sentinel controlled loop. The control for the loop is to continue
> > entering
> > > names until a "-1" is encountered.
> > >
> > > First time through the loop
> > >
> > > Private Sub cmdName_Click()
> > > Dim LName(20) As String, FName(20) As String
> > > Dim Number As Integer
> > > Number = 0
> > > ' Use sentinel-controlled program to control entering names
> > > lstStudents.Clear
> > > lstStudents.AddItem "Last Name" & vbTab & "First Name"
> > > LName(Number) = InputBox("Enter Last Name; -1 to end",
> "VBHTP")
> > > FName(Number) = InputBox("Enter First Name;", "VBHTP")
> > > Do Until LName(Number) = -1
> > > Number = Number + 1
> > > LName(Number) = InputBox("Enter Last Name; -1 to end",
> "VBHTP")
> > > FName(Number) = InputBox("Enter First Name;", "VBHTP")
> > > Loop
> > > End Sub
> > >
> > > At the Statement with the comparison to -1, I get a type mismatch
error
> on
> > > execution.
> > >
> > > Does VB allow a comparion of a string variable (in an array) to an
> integer
> > > or does either the string variable
> > > or integer have to be changed to make the comparison?
> > >
> > > any help or comments or suggestions would be appreciated. Also, this
> > method
> > > seems cumbersome,
> > > any suggestions to something a little more elegant
> > >
> > > Thanks ahead of time.
> > >
> > > David
> >
> >
>
>