• 0

[VB6] Boolean Function


Question

What needs to be changed or added for the following code to work? I program mostly in Java now, and I've forgotten alot of my Visual Basic.

Option Explicit

Private Sub cmdEncode_Click()

    Dim key1 As String
    Dim key2 As String
    
    key1 = UCase(txtKey1.Text)
    key2 = UCase(txtKey2.Text)
    
    If ValidateKey(key1, "Validating key 1...", "Key 1 not valid!") = False Then
        Exit Sub
    End If
    
    If ValidateKey(key2, "Validating key 2...", "Key 2 not valid!") = False Then
        Exit Sub
    End If
    
    Dim i As Integer
    
   
    For i = 1 To Len(key1)
        ProgressBar.Value = i

        Dim x As Integer
        For x = 0 To i - 1
            If lblKey1(x).Caption <> Mid(key1, i, 1) Then
                lblKey1(i - 1).Caption = Mid(key1, i, 1)
            End If
        Next x
    Next i
    
    
End Sub

Private Function ValidateKey(ByVal key As String, ByVal status As String, ByVal error As String) As Boolean
    
    Dim check(Len(key)) As String
    Dim i As Integer
    
    lblStatus.Caption = status
    ProgressBar.Min = 1
    ProgressBar.Max = Len(key)

    
    For i = 1 To Len(key)
        ProgressBar.Value = i
    
        Dim x As Integer
        For x = 0 To i - 1
            If check1(x) <> Mid(key, i, 1) Then
                check1(i - 1) = Mid(key, i, 1)
            Else
                ProgressBar.Value = 0
                lblStatus.Caption = error
                ValidateKey = False
                Exit Function
            End If
        Next x
    Next i
    
    ValidateKey = True
End Function

This throws the following error:

  Quote
Compile error:

Constant expression required

When you follow the debug it takes you to these lines:

Private Function ValidateKey(ByVal key As String, ByVal status As String, ByVal error As String) As Boolean
    
    Dim check(Len(key)) As String

It highlights the function with yellow and then selects the text "key" in "Len(key)" as the source of the error.

Link to comment
https://www.neowin.net/forum/topic/398028-vb6-boolean-function/
Share on other sites

15 answers to this question

Recommended Posts

  • 0

Alright, that worked beautifully! Thank you. I have another problem. This code does not do what it is supposed to do! >:-( I'm trying to scan a word to make sure that a letter is only used once in the whole string. If anyone can see why this code doesn't work, your help would be appreciated!

EDIT: Nevermind, very simple logic mistake, just had to change the order of the if and the second for loop! Thanks again for the help!

Edited by Delox
  • 0

Once again, it was a simple mistake. I have a new problem with a sub routine. I'm trying to make it fill the remaining labels in a row with letters from the alphabet that are not used. So far the program looks like this:

Option Explicit

Private Sub cmdEncode_Click()

    Dim key1 As String
    Dim key2 As String
    
    key1 = UCase(txtKey1.Text)
    key2 = UCase(txtKey2.Text)
    
    If ValidateKey(key1, "Validating key 1...", "Key 1 not valid!") = False Then
        Exit Sub
    End If
    
    If ValidateKey(key2, "Validating key 2...", "Key 2 not valid!") = False Then
        Exit Sub
    End If
    
    Dim i As Integer
    
    ProgressBar.Min = 0
    ProgressBar.Max = Len(key1)
    lblStatus.Caption = "Assigning headers..."
    For i = 1 To Len(key1)
        ProgressBar.Value = i

        Dim x As Integer
        For x = 0 To i - 1
            If lblKey1(x).Caption <> Mid(key1, i, 1) Then
                lblKey1(i - 1).Caption = Mid(key1, i, 1)
            End If
        Next x
    Next i
    
    Call finishRow(-1, i)
    
    lblStatus.Caption = "Done!"
End Sub

Private Sub finishRow(ByVal row As Integer, ByVal pos As Integer)
    ProgressBar.Min = pos
    ProgressBar.Max = UBound(lblKey1) - pos
    lblStatus.Caption = "Assigning headers..."
    
    Dim asc As Integer
    asc = asc("A")
    
    If row = -1 Then
        Dim i As Integer
        
        For i = pos To 25
            ProgressBar.Value = i
            Dim x As Integer
            
            For x = 0 To i
                If asc = lblKey1(x) Then
                    asc = asc + 1
                End If
            Next x
            
            lblKey1(i).Caption = Chr(asc)
        Next i
    End If
End Sub

Private Function ValidateKey(ByVal key As String, ByVal status As String, ByVal error As String) As Boolean
    ProgressBar.Value = 0
    
    If Len(key) = 0 Then
        ProgressBar.Value = ProgressBar.Max
        lblStatus.Caption = error
        ValidateKey = False
        Exit Function
    End If
    
    Dim check() As String
    ReDim check(Len(key))
    
    Dim i As Integer
    
    For i = 1 To Len(key)
        check(i - 1) = Mid(key, i, 1)
    Next i
    
    lblStatus.Caption = status
    ProgressBar.Min = 0
    ProgressBar.Max = Len(key)

    
    For i = 0 To Len(key)
        ProgressBar.Value = i
        
        Dim x As Integer
        For x = 0 To i - 1
            Dim s As String
            
            s = Mid(key, i, 1)
            If asc(s) < asc("A") Or asc(s) > asc("Z") Then
                ProgressBar.Value = ProgressBar.Max
                lblStatus.Caption = error
                ValidateKey = False
                Exit Function
            End If
            
            If x <> i - 1 And check(x) = s Then
                ProgressBar.Value = ProgressBar.Max
                lblStatus.Caption = error
                ValidateKey = False
                Exit Function
            End If
        Next x
    Next i
    
    ValidateKey = True
    
End Function

Private Sub Form_Load()
    Dim i As Integer
    Dim c As Integer
    
    c = asc("A")
    
    For i = 0 To 25
        lblKey1(i).Caption = Chr(c)
        c = c + 1
    Next i
    
    For i = 0 To 9
        lblRow(i).Caption = i
    Next i
End Sub

At this point:

Private Sub finishRow(ByVal row As Integer, ByVal pos As Integer)

it shows the error:

  Quote
Compile error:

Expected array

Once again, I have no idea what the problem is. I haven't used Visual Basic 6 in a while...

  • 0

For i = pos To 25

ProgressBar.Value = i

Dim x As Integer

For x = 0 To i

If asc = lblKey1(x) Then

asc = asc + 1

End If

Next x

lblKey1(i).Caption = Chr(asc)

Next i

looks a little dodgy, you're comparing an int asc to a label control for equality? (Don't rely on default props)

asc never gets reset in any of the loops. Is this correct? :unsure

  • 0

asc doesn't need to be reset, as this part of the code only runs once. There will be an else section here where it will figure out which row the user is at, and use a second (10 letter) keyword to shift the alphabetical letters as far right as that postion, and print the alphabet from that point on, looping back to A, like this:

key 1 = nosamechr

key 2 = chrnotsame (this key MUST be 10 letters, which will be added later)

I need to create a table like this one below:

   | N O S A M E C H R B D F G I J K L P Q T U V W X Y Z
--+----------------------------------------------------
0 | C D E F G H I J K L M N O P Q R S T U V W X Y Z A B
1 | H I J K L M N O P Q R S T U V W X Y Z A B C D E F G
2 | R S T U V W X Y Z A B C D E F G H I J K L M N O P Q
3 | N O P Q R S T U V W X Y Z A B C D E F G H I J K L M
4 | O P Q R S T U V W X Y Z A B C D E F G H I J K L M N
5 | T U V W X Y Z A B C D E F G H I J K L M N O P Q R S
6 | S T U V W X Y Z A B C D E F G H I J K L M N O P Q R
7 | A B C D E F G H I J K L M N O P Q R S T U V W X Y Z
8 | M N O P Q R S T U V W X Y Z A B C D E F G H I J K L
9 | E F G H I J K L M N O P Q R S T U V W X Y Z A B C D

A call to the sub finishRow(ByVal row As Integer, ByVal pos As Integer) which is "finishRow(-1, i) should complete the first line of letters (row X). I will latter add code to scan a word, take each letter and assign it to a row. It will start the alphabet from that letter, and then complete the row. Row 2 for example starts with "R" the alphabet is then finished and it loopes back to the start to complete the row.

Hopefully this will help you understand what I'm trying to accomplish. If you can think of a better way of doing this, any help would be appreciated!

  • 0

Here is the code to produce the grid using two keys ( I think this is what you want!)

I have sent the output to a text box for brevity but you could build a two dimensional array and then populate labels or create labels dynamicaly

Hope it makes sense:

Option Explicit

Private mAlphabet(25) As String

Private Sub BuildAlphabet()

Dim i As Integer

For i = 0 To 25

mAlphabet(i) = Chr(CLng(Asc("A") + i))

Next i

End Sub

Private Function BuildHeaderLine(key As String) As String

Dim ret As String

Dim i As Integer

ret = key

For i = 0 To 25

If InStr(1, key, mAlphabet(i)) = 0 Then

ret = ret & mAlphabet(i)

End If

Next i

BuildHeaderLine = ret

End Function

Private Function BuildLine(letter As String) As String

Dim ret As String

ret = letter

Dim startPos As Integer

startPos = Asc(letter) - Asc("A") + 1

Dim i As Integer

For i = startPos To startPos + 24

ret = ret & mAlphabet(i Mod 26)

Next i

BuildLine = ret

End Function

Private Sub Command1_Click()

Dim key1 As String

Dim key2 As String

key1 = UCase("nosamechr")

key2 = UCase("chrnotsame")

Call BuildAlphabet

Text1.Text = BuildHeaderLine(key1) + vbCrLf

Dim i As Integer

Dim letter As String

For i = 1 To Len(key2)

letter = Mid$(key2, i, 1)

Text1.Text = Text1.Text + BuildLine(letter) + vbCrLf

Next i

End Sub

  • 0

I've got to admit, you used some techniques there I would have never thought of! Using inStr to see if a character is used should have been obvious. The real genious is in using modulus to figure out the characters to complete the lines.

I have few more questions though:

How exactly would you go about putting this information into an array?? What I need to be able to do is reference a letter in the body using it's row number and the letter in the header for the column, as is seen on this page. It should be simple once I know how to create the table, either in memory, or as an actual table using label boxes. Any thoughts?

  • 0

Option Explicit

Private mAlphabet(25) As String


Private mOutputTable(10, 25) As String


Private Sub BuildAlphabet()
Dim i As Integer
    For i = 0 To 25
        mAlphabet(i) = Chr(CLng(Asc("A") + i))
    Next i

End Sub

Private Function BuildHeaderLine(key As String) As String
Dim ret As String
Dim i As Integer

    ret = key
    
    For i = 0 To 25
        If InStr(1, key, mAlphabet(i)) = 0 Then
            ret = ret & mAlphabet(i)
        End If
    Next i
    

    BuildHeaderLine = ret
End Function

Private Function BuildLine(letter As String, lineNo As Integer) As String
    Dim ret As String
    
    ret = letter
    mOutputTable(lineNo, 0) = letter
    
    
    Dim startPos As Integer
    
    startPos = Asc(letter) - Asc("A") + 1
    
    Dim i As Integer
    
    For i = startPos To startPos + 24
        mOutputTable(lineNo, i - startPos + 1) = mAlphabet(i Mod 26)
        ret = ret & mAlphabet(i Mod 26)
    Next i
    
    BuildLine = ret
End Function


Private Sub LetterAtPos(lineNumber As Integer, col As String, key As String)
Dim letter As String
Dim letterPos As Integer

    letterPos = InStr(1, key, col) - 1
    
    If letterPos > -1 Then
        letter = mOutputTable(lineNumber, letterPos)
        Call MsgBox("Letter Is: " + letter)
    Else
        Call MsgBox("Error")
    End If

End Sub



Private Sub Command1_Click()
    
    Dim key1 As String
    Dim key2 As String
    Dim columnKey As String
    
    key1 = UCase("nosamechr")
    key2 = UCase("chrnotsame")
    
    Call BuildAlphabet
    columnKey = BuildHeaderLine(key1)
    Text1.Text = columnKey + vbCrLf
    Text1.Text = Text1.Text + String(26, "=") + vbCrLf

Dim i As Integer
Dim j As Integer
Dim letter As String

    For i = 1 To Len(key2)
        letter = Mid$(key2, i, 1)
        Call BuildLine(letter, i - 1)
    Next i
    
    For i = 1 To Len(key2)
        For j = 0 To 25
            Text1.Text = Text1.Text + mOutputTable(i - 1, j)
        Next j
        Text1.Text = Text1.Text + vbCrLf
    Next i
    
    Call LetterAtPos(5, "R", columnKey)


End Sub

Should do it for you

This topic is now closed to further replies.
  • Recently Browsing   0 members

    • No registered users viewing this page.
  • Posts

    • Nice! My $100 refurbished iPad 8 that I bought last year for a small project (and still runs like new cuz it's been mostly in storage the past several months) will get this v26 upgrade. I'm definitely gonna scope out OS26 on this device before upgrading my also-supported refurbished iPhone SE 3rd Gen (only got it for the 5G UW support).
    • Hello, The separate discussion about VLC has been moved to its own thread at  Regards, Aryeh Goretsky  
    • Hello, I am guessing this is the result of using a third-party tweaking tool instead of changing things within Windows settings. Windows 11 has a decent set of configuration options for the display, but they tend to be scattered throughout the operating system due to fragmentation of product ownership/inconsistent standards being applied by Microsoft. There are a few places in Windows 11 where you can modify the various display settings in order to get them to your liking: Under Settings → System → Display you can stroll down to the Scale & layout section and change the Scale and Display resolution settings to whatever you prefer.  For the Scale option, you can click on the text box to choose between the various pre-populated settings.  If none of those are exactly what you are looking for, click on the caret ("") caret to open the Custom scaling setting (also available under Settings → Display → Custom scaling).  I would recommend this as an option of last resort as this can cause display issues in various programs. I strongly recommend using the screen's native Display resolution here; it should show up as the "(Recommended)" resolution.  If it does not, you may need to install your monitor's profile information file (basically, a device driver for your monitor) to get the correct setting. Another place to look at making changes to fonts is under Accessiblity → Text size.  There is a slider bar for changing the text size from 100% to 225% there. You can try making changes to the ClearType settings.  It's a little bit finer-grained than the others, but it may make the text easier to view on the display.  Run the ClearType Text Tuner (filename: CTTUNE.EXE) and go through the wizard. You may want to do this several times under different lighting conditions or times of the day to figure out what works best for you overall. Lastly, you may want to look into using a dedicated assistive screen technology program from a third-party.  Microsoft provides a Screen Magnifier and a Narrator for text-to-speech, but they provide only basic functionality, and you may find that a third-party program works a lot better.  The pros of this is that third-party assistive technology programs tend to work quite well under Windows; Microsoft has historically worked closely with third-party developers of assistive technologies.  The cons of this are that such tools tend to be on the expensive side, since they are often sold to schools, businesses, or paid for by insurance companies, not individuals. Regards, Aryeh Goretsky  
    • Totally agree with you. I think people, especially on tech sites, need to realize that they’re the minority. Microsoft isn’t going to waste time on things that, in the big picture, don’t matter to the majority.
    • I think a lot of people here are too young to even remember Aqua.
  • Recent Achievements

    • Dedicated
      MadMung0 earned a badge
      Dedicated
    • Rookie
      CHUNWEI went up a rank
      Rookie
    • Enthusiast
      the420kid went up a rank
      Enthusiast
    • Conversation Starter
      NeoToad777 earned a badge
      Conversation Starter
    • Week One Done
      VicByrd earned a badge
      Week One Done
  • Popular Contributors

    1. 1
      +primortal
      506
    2. 2
      ATLien_0
      267
    3. 3
      +FloatingFatMan
      257
    4. 4
      Edouard
      203
    5. 5
      snowy owl
      178
  • Tell a friend

    Love Neowin? Tell a friend!