Encode and Decode VBA Program - vb.net

Question

in my programming class I have to create a program which allows the user in order to enter a sentence, with the buttons "Encode" and "Decode" as options. So, for "Encode", you have to translate the sentence into Asc numbers (already did this). However, I'm currently stuck on the "Decode" section, for you have to use a For loop and an array to separate the Asc numbers by spaces, then translate them into characters one by one. Here's what I have so far:
Public Class Form1
Dim Message As String
Dim NewMessage As String
Dim Part As String
Dim Part2 As Integer
Dim Letter As String
Dim Length As String
Dim ints() As Integer
Dim intlength As Integer
Private Sub btn_Enter_Click(sender As Object, e As EventArgs) Handles btn_Enter.Click
Message = txt_Message.Text
Length = Message.Length() - 1
If rbn_Encode.Checked = True Then
For Num As Integer = 0 To Length
Letter = Message(Num)
Me.lbl_Code.Text = lbl_Code.Text & Asc(Letter) & " "
Next
End If
If rbn_Decode.Checked = True Then
For Num As Integer = 0 To intlength Step 1
If Message(Num) <> " " Then
Part = Part & Message(Num)
Else
NewMessage = NewMessage & ChrW(Part) & " "
End If
Next
Me.lbl_Code.Text = NewMessage
End If
End Sub
Private Sub ExitToolStripMenuItem_Click(sender As Object, e As EventArgs) Handles ExitToolStripMenuItem.Click
Application.Exit()
End Sub
End Class
I've been stuck on this for about 2 week, and I'm still clueless. Thank you for your help and have a wonderful day.

Answer 1

This might seem to veer off the topic of the question, but it all meanders towards a better answer.
OK there are a few issues with your code. Firstly, make sure that "Option Strict" is on - have a look here. This will force you to convert types properly and reduce the potential for problems. Bearing the above in mind,
Dim Length As String
should be
Dim Length As Integer
on to the next bit
Each procedure should have a single responsibility. Your btn_Enter.Click event handler includes code for encoding text and decoding numbers. These should be separated out into their own procedures. In a relatively short bit of code like yours, it's not too much of a problem, but even here, it makes things a little fuzzier. Have a look at the code below. There are more issues, but we'll look at them in a moment. The code below is a bit clearer and more maintainable.
Private Sub btn_Enter_Click(sender As Object, e As EventArgs) Handles btn_Enter.Click
Message = txt_Message.Text
Length = Message.Length() - 1
If rbn_Encode.Checked = True Then
EncodeTextToAscii()
End If
If rbn_Decode.Checked = True Then
DecodeToText()
End If
End Sub
Private Sub DecodeToText()
For Num As Integer = 0 To intlength Step 1
If Message(Num) <> " " Then
Part = Part & Message(Num)
Else
NewMessage = NewMessage & ChrW(Part) & " "
End If
Next
Me.lbl_Code.Text = NewMessage
End Sub
Private Sub EncodeTextToAscii()
For Num As Integer = 0 To Length
Letter = Message(Num)
Me.lbl_Code.Text = lbl_Code.Text & Asc(Letter) & " "
Next
End Sub
Next.
In your code to encode the string as ASCII, you store the resulting data directly in the label lbl_Code's text property. The user interface should never be used as the primary store for data. It's bad practice and potentially allows the user to change data accidentally - in textboxes for example. In the case of a label, it's not to important, but it's far better to get into the good habits.
To store your encoded ASCII numbers, you can use the array ints, but as your code stands, the declaration of ints is just that. There is no space in the array to store data. So, in the Encode procedure, you need to resize ints to the same as the number of characters in the string.
So now we have ..
Private Sub EncodeTextToAscii()
ReDim ints(Length)
For Num As Integer = 0 To Length
Letter = Message(Num)
ints(Num) = Asc(Letter)
Next
End Sub
Finally onto the meat of your question. The Decode procedure can now be written as this ..
Private Sub DecodeToText()
NewMessage = ""
For Each asciiNumber As Integer In ints
NewMessage = NewMessage & ChrW(asciiNumber) & " "
Next
Me.lbl_Code.Text = NewMessage
End Sub
Instead of mucking around getting the length of a loop and getting the ascii number in each element of an array, you can simplyfy it using a For Each statement. You dont need to know the length of the array. It just loops over the whole length. Much easier.
As an excercise, try applying the For Each idea to the Encode procedure. :-)