[RESOLVED] Counting using the alphabet

[stanav]

Hello all,
How do I properly increment (counting) a number using the alphabet? For example,
a + 1 = b
b + 1 = c
......
z + 1 = aa
aa + 1 = ab
.......
Any help is greatly appreciated.

[NPassero]

i would use the character values..

chr(97) = a
chr(98) = b

if value > 122 then ' value for z
chr(97) & chr(value - 25)

i think.

edit. this is confusing me. sorry if i made it worse.

[nmadd]

I don't know if this will help:
http://www.freevbcode.com/ShowCode.asp?ID=5440

[NPassero]

Public Sub Numbers()
 
      Dim s As String               ' String value
      Dim v As Integer             ' Character increment
      Dim x As Integer = -1       ' Used for multiple characters
      Dim p As Integer = 97       ' Start of characters.. (97 = a)
 
      For i As Integer = 0 To 200
 
         v = i + p
 
         If (v = 123) Then
            x += 1
            p -= 27
         Else
 
            If x > -1 Then
 
               s = Chr(97 + x) & Chr(v)
 
            Else
 
               s = Chr(v)
 
            End If
 
            Console.WriteLine(s)
 
         End If
 
      Next
 
   End Sub

edit.
works up to zz properly... zz = 728

[stanav]

I don't know if this will help:
http://www.freevbcode.com/ShowCode.asp?ID=5440

Yeah, that's it... It gave me an idea about the logic behind... Just have to rewrite it using proper VB.Net code
Thank you.

[nmadd]

You certainly helped me many times, so I'm glad I could finally help you.

[VBDT]

I believe you can use the "Asc" method to get the caracter's ASCI code and than add one to it and show the total number by Chr method. Here an example:

Dim myAsci As Integer
myAsci = Asc("a") + 1
Debug.WriteLine(Chr(myAsci))

for the "aa + 1 = ab" you use the same logic. For example the "a" letter asci is 97 and "z"'s is 121 and any thing between are other letters. You can have a flag that if the characters asci + 1 is less than 122 than return Chr(asci).

Here is the method

Private Function SomeThing(ByVal myString As String, ByVal num As Integer) As String
        Dim lastChar As Char = myString.Substring(myString.Length - 1)
        Dim asci As Integer = Asc(lastChar) + num
        If asci > 122 Then
            myString = myString.Substring(0, myString.Length - 1) & "aa"
        Else
            myString = myString.Substring(0, myString.Length - 1) & Chr(asci)
        End If
        Return myString
    End Function

[stanav]

Thank you all who have spent your precious time solving my question... You guys are really helpful

To NPassero: while I have no doubt that your code would work correctly up to "zz", however I need a more robust solution - a function that takes a string a spits out the next incremented string regardless of the input length. Your solution seems to work with pre-known, fixed string length only.

To VBDT: Your function does something different than what I expect.... For example, If I plug in "zz", I expect to see the output as "aaa", not "zaa"

Anyway, this is the solution, in case someone else is also looking to do the same thing as I'm...

Private Function IncrementString(ByVal input As String) As String
        Dim output As String = String.Empty
        Dim length As Integer = input.Length
        Dim curChar As Char = Nothing
        Dim i As Integer = 0
        If String.IsNullOrEmpty(input) Then
            output = "a"
        Else
            For i = length - 1 To 0 Step -1
                curChar = input(i)
                If curChar = "z"c Then
                    input = input.Substring(0, i) & "a" & input.Substring(i + 1)
                    If i = 0 Then
                        input = "a" & input
                    End If
                Else
                    input = input.Substring(0, i) & Chr(Asc(curChar) + 1) & input.Substring(i + 1)
                    Exit For
                End If
            Next
            output = input
        End If
        Return output
    End Function

[NPassero]

Gotcha, didn't know the functionality that you were using it for. good work.