Recursive call is causing error.

[get2noesks]

The code is failing on the red marked line. Can someone please help me with it.

<code>

Private Sub Workbook_Open()
Dim WS1 As Worksheet
Dim WS2 As Worksheet

Set WS1 = Worksheets("Sheet1")
Set WS2 = Worksheets("Sheet2")

Dim testCollection As Collection
Dim SIZE As Integer, sortCol As Integer, sortRow As Integer, loopcntl As Integer
Set testCollection = getValuesToSort
'Debug.Print testCollection.Item(3)

'Debug.Print testCollection.Count
sortRow = 1
loopcntl = 1
SIZE = testCollection.Count
If SIZE <= 0 Then
MsgBox ("Nothing To Search for a sort")
End If

For loopcntl = 1 To SIZE
'MsgBox (loopCntl)
'MsgBox testCollection.Item(loopCntl)
'Call sortData(sortRow, loopCntl)
Dim completeArray() As String, arrayLeft() As String, arrayRight() As String
Dim arrayInputCntlVar As Integer, firstIndex As Integer
firstIndex = sortRow
arrayInputCntlVar = testCollection.Item(loopcntl)

Dim i As Integer, arrSize As Integer
i = 0

arrSize = WorksheetFunction.CountA(WS1.Columns(arrayInputCntlVar))
MsgBox (arrSize)
ReDim completeArray(arrSize)

While (WS1.Cells(sortRow + 1, arrayInputCntlVar)) <> ""
completeArray(i) = WS1.Cells(sortRow + 1, arrayInputCntlVar).Value
sortRow = sortRow + 1
i = i + 1
Wend

Dim lastIndex As Integer
lastIndex = i + 1
Call MergeSort(completeArray(), firstIndex, lastIndex)



Next loopcntl

End Sub

Public Sub MergeSort(list() As String, ByVal first_index As Integer, ByVal last_index As Integer)
Dim middle As Integer
If (last_index > first_index) Then
' Recursively sort the two halves of the list.
middle = (first_index + last_index) / 2

Call MergeSort(list, first_index, middle)

Call MergeSort(list, middle + 1, last_index)

' Merge the results.
Call Merge(list, first_index, middle, last_index)
End If
End Sub

Public Sub Merge(list() As String, ByVal beginning As Integer, ByVal middle As Integer, ByVal ending As Integer)
Dim temp_array() As String
Dim temp As Integer
Dim counterA As Integer
Dim counterB As Integer
Dim counterMain As Integer

' Copy the array into a temporary array.
ReDim temp_array(beginning To ending)
CopyMemory temp_array(beginning), list(beginning), (ending - beginning + 1) * Len(list(beginning))

' counterA and counterB mark the next item to save
' in the first and second halves of the list.
counterA = beginning
counterB = middle + 1

' counterMain is the index where we will put the
' next item in the merged list.
counterMain = beginning
Do While (counterA <= middle) And (counterB <= ending)
' Find the smaller of the two items at the front
' of the two sublists.
If (temp_array(counterA) <= temp_array(counterB)) _
Then
' The smaller value is in the first half.
list(counterMain) = temp_array(counterA)
counterA = counterA + 1
Else
' The smaller value is in the second half.
list(counterMain) = temp_array(counterB)
counterB = counterB + 1
End If
counterMain = counterMain + 1
Loop

' Copy any remaining items from the first half.
If counterA <= middle Then
CopyMemory list(counterMain), temp_array(counterA), (middle - counterA + 1) * Len(list(beginning))
End If

' Copy any remaining items from the second half.
If counterB <= ending Then
CopyMemory list(counterMain), temp_array(counterB), (ending - counterB + 1) * Len(list(beginning))
End If
End Sub

</code>

Regards
Saurabh

 

[StephenCrump]

It's not immediately obvious what your code is trying to do.

But when you say "The code is failing", I am guessing that you are getting an "Out of Stack Space" error?

If you step through just this next snippet of code, when last_index>first_index on the first call ...

Public Sub MergeSort(list() As String, ByVal first_index As Integer, ByVal last_index As Integer)
    
    Dim middle As Integer
    
    If (last_index > first_index) Then
        ' Recursively sort the two halves of the list.
        middle = (first_index + last_index) / 2
        
        Call MergeSort(list, first_index, middle)
        '...

... then you'll quickly see that last_index will always remain > first_index, and you're stuck in a recursive loop.

For example, if you call MergeSort with first_index = 1 and last_index = 5 (say), this snippet will trigger:

Call MergeSort(list, 1,3), which will trigger
Call MergeSort(list, 1,2), which will trigger
Call MergeSort(list, 1,2), which will trigger
Call MergeSort(list, 1,2), which will trigger
.....

I suspect there will be other problems with your code, e.g. as written, the second half of your list won't get sorted until the recursion has bottomed out on the first half, and in the meantime you are changing the value of middle on each iteration.

 

[CharlesChuckieCharles]

<code>It will continually call itself</code>

better to use a control routine to explicitly call the sorts

 

[get2noesks]

Thanks guys..!! I modified the infinite recursive and it worked.