Ravine Enivar

J-Walk posted about the word ‘ravine’. If you spell it backwards, each letter is offset 13 characters from its forward-spelled cousin. He says:

Who can come up with another? You may use Excel.

I came up with these using the list of words at orchy.com:

ravine enivar immediate window

although I’m not sure how some of those are words. I pasted the dictionary in a text file. Then I tried to replace all of the spaces with commas. I killed notepad.exe after about 20 minutes, deciding to parse the strings in VBA instead.

Sub Enivar()
   
    Dim sFname As String
    Dim lFnum As Long
    Dim sInput As String
    Dim vaWords As Variant
    Dim i As Long
    Dim sWord As String
   
    ‘identify the file
   sFname = Environ$(“USERPROFILE”) & “My Documentsorchydict.txt”
    lFnum = FreeFile
   
    ‘open the file
   Open sFname For Input As lFnum
   
    Do While Not EOF(lFnum) ‘loop until the end
       Input #lFnum, sInput ‘read in a chunk of data
       vaWords = Split(sInput, ” “) ‘split the word on space
       For i = LBound(vaWords) To UBound(vaWords)
            sWord = UCase(vaWords(i)) ‘make everything upper case
           If ReverseString(sWord) = OffsetString(sWord) Then
                Debug.Print sWord
            End If
        Next i
    Loop
   
    Close lFnum ‘close the file
   
End Sub
 
Function ReverseString(sWord As String) As String
   
    Dim i As Long
    Dim sReturn As String
   
    For i = Len(sWord) To 1 Step -1 ‘loop backward
       sReturn = sReturn & Mid(sWord, i, 1)
    Next i
   
    ReverseString = sReturn
   
End Function
 
Function OffsetString(sWord As String) As String
   
    Dim i As Long
    Dim sReturn As String
    Dim sLetter As String
    Dim lAscZ As Long, lAscAm As Long
   
    Const lOFF As Long = 13
   
    lAscZ = Asc(“Z”)
    lAscAm = Asc(“A”) – 1
   
    For i = 1 To Len(sWord)
        sLetter = Mid$(sWord, i, 1)
        ‘move 13 letters forward, wrap around to A if necessary
       If Asc(sLetter) + lOFF > lAscZ Then
            sReturn = sReturn & Chr$(((Asc(sLetter) + lOFF) Mod lAscZ) + lAscAm)
        Else
            sReturn = sReturn & Chr$(Asc(sLetter) + lOFF)
        End If
    Next i
   
    OffsetString = sReturn
   
End Function
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9 thoughts on “Ravine Enivar

  1. Don’t know how much these improvements help but here they are.

    First, recognize that words that meet the requirement must have an even number of characters.

    Second, compare the 1st half of each word with the last half working from the outside in.

    Third, the character-by-character test can stop at the first failure.

    Combining the above:

    Option Explicit

    Sub Enivar()
       
        Dim sFname As String, lFnum As Long, sInput As String
       
        sFname = “c: emporchydict.txt”
        lFnum = FreeFile
       
        Open sFname For Input As lFnum
        Do While Not EOF(lFnum)
            Input #lFnum, sInput
            Dim vaWords As Variant, I As Long
            vaWords = Split(sInput, ” “)
            For I = LBound(vaWords) To UBound(vaWords)
                If Offset13(vaWords(I)) Then Debug.Print vaWords(I)
                Next I
            Loop
        Close lFnum
        End Sub

    Function Offset13(ByVal aWord As String) As Boolean
        Dim I As Integer, WordLen As Integer
        WordLen = Len(aWord)
        If WordLen Mod 2 <> 0 Then Exit Function
        aWord = UCase(aWord)
        For I = 1 To Len(aWord) / 2
            If Abs(Asc(Mid(aWord, I, 1)) – Asc(Mid(aWord, WordLen + 1 – I, 1))) <> 13 Then _
                Exit Function
            Next I
        Offset13 = True
        End Function

    The resulting list:
    an
    bo
    CP
    Er
    fans
    fobs
    freres
    gant
    gnat
    grivet
    GT
    Hu
    iv
    Livy
    Lyly
    na
    nana
    Ob
    pc
    ravine
    re
    rebore
    rive
    robe
    serf
    SF
    tang
    TG
    thug
    uh
    vi

  2. It’s good to see the VBA community is really getting to grips with the major technological challenges of the 21st century :-) Ah well, back to that perpetual motion machine …

  3. Hi Dick –

    No need to roll your own ReverseString(). There’s StrReverse() in VBA6.

    …mrt

  4. Mine takes 4.9 seconds. Tushar’s takes 4.5 seconds. Using the built in StrReverse in Tushar’s took 3.6 seconds.

    Now how did I not now about StrReverse?

    Roy: We once spelled words using Excel’s column headings, so there’s nowhere to go but up. :)

  5. Notepad is only good for a screenful or two of ‘search n replace’. I joined some colelagues on a job once which involved them starting off a very large S’n’R in Notepad and then saying “Right, that’s lunch, it’ll take an hour to run”, my helpful suggestion to use Word and do it in 2 seconds was welcomed with open arms.

    Gareth

    Hawaiian Tropic Talent Scouting Agency (Elephant Island Office – Antarctica)

  6. Hi Dick –

    After reaching a certain maturity, whenever something comes into memory, something goes out. :-) And we’re not given to know what goes out. At least that’s how it is for me. Memory is third thing to go, and I forgot what the other two are.

    Potential MIDW posted over at Doug’s site.

    …mrt

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