https://stackoverflow.com/a/19415281

QuickSortNaturalNum.bas

Public Sub QuickSortNaturalNum(strArray() As String, intBottom As Integer, intTop As Integer)
Dim strPivot As String, strTemp As String
Dim intBottomTemp As Integer, intTopTemp As Integer

    intBottomTemp = intBottom
    intTopTemp = intTop

    strPivot = strArray((intBottom + intTop) \ 2)

    Do While (intBottomTemp <= intTopTemp)
        ' < comparison of the values is a descending sort
        Do While (CompareNaturalNum(strArray(intBottomTemp), strPivot) < 0 And intBottomTemp < intTop)
            intBottomTemp = intBottomTemp + 1
        Loop
        Do While (CompareNaturalNum(strPivot, strArray(intTopTemp)) < 0 And intTopTemp > intBottom) '
            intTopTemp = intTopTemp - 1
        Loop
        If intBottomTemp < intTopTemp Then
            strTemp = strArray(intBottomTemp)
            strArray(intBottomTemp) = strArray(intTopTemp)
            strArray(intTopTemp) = strTemp
        End If
        If intBottomTemp <= intTopTemp Then
            intBottomTemp = intBottomTemp + 1
            intTopTemp = intTopTemp - 1
        End If
    Loop

    'the function calls itself until everything is in good order
    If (intBottom < intTopTemp) Then QuickSortNaturalNum strArray, intBottom, intTopTemp
    If (intBottomTemp < intTop) Then QuickSortNaturalNum strArray, intBottomTemp, intTop
End Sub

Function CompareNaturalNum(string1 As Variant, string2 As Variant) As Integer
'string1 is less than string2 -1
'string1 is equal to string2 0
'string1 is greater than string2 1
Dim n1 As Long, n2 As Long
Dim iPosOrig1 As Integer, iPosOrig2 As Integer
Dim iPos1 As Integer, iPos2 As Integer
Dim nOffset1 As Integer, nOffset2 As Integer

    If Not (IsNull(string1) Or IsNull(string2)) Then
        iPos1 = 1
        iPos2 = 1
        Do While iPos1 <= Len(string1)
            If iPos2 > Len(string2) Then
                CompareNaturalNum = 1
                Exit Function
            End If
            If isDigit(string1, iPos1) Then
                If Not isDigit(string2, iPos2) Then
                    CompareNaturalNum = -1
                    Exit Function
                End If
                iPosOrig1 = iPos1
                iPosOrig2 = iPos2
                Do While isDigit(string1, iPos1)
                    iPos1 = iPos1 + 1
                Loop

                Do While isDigit(string2, iPos2)
                    iPos2 = iPos2 + 1
                Loop

                nOffset1 = (iPos1 - iPosOrig1)
                nOffset2 = (iPos2 - iPosOrig2)

                n1 = Val(Mid(string1, iPosOrig1, nOffset1))
                n2 = Val(Mid(string2, iPosOrig2, nOffset2))

                If (n1 < n2) Then
                    CompareNaturalNum = -1
                    Exit Function
                ElseIf (n1 > n2) Then
                    CompareNaturalNum = 1
                    Exit Function
                End If

                ' front padded zeros (put 01 before 1)
                If (n1 = n2) Then
                    If (nOffset1 > nOffset2) Then
                        CompareNaturalNum = -1
                        Exit Function
                    ElseIf (nOffset1 < nOffset2) Then
                        CompareNaturalNum = 1
                        Exit Function
                    End If
                End If
            ElseIf isDigit(string2, iPos2) Then
                CompareNaturalNum = 1
                Exit Function
            Else
                If (Mid(string1, iPos1, 1) < Mid(string2, iPos2, 1)) Then
                    CompareNaturalNum = -1
                    Exit Function
                ElseIf (Mid(string1, iPos1, 1) > Mid(string2, iPos2, 1)) Then
                    CompareNaturalNum = 1
                    Exit Function
                End If

                iPos1 = iPos1 + 1
                iPos2 = iPos2 + 1
            End If
        Loop
        ' Everything was the same so far, check if Len(string2) > Len(String1)
        ' If so, then string1 < string2
        If Len(string2) > Len(string1) Then
            CompareNaturalNum = -1
            Exit Function
        End If
    Else
        If IsNull(string1) And Not IsNull(string2) Then
            CompareNaturalNum = -1
            Exit Function
        ElseIf IsNull(string1) And IsNull(string2) Then
            CompareNaturalNum = 0
            Exit Function
        ElseIf Not IsNull(string1) And IsNull(string2) Then
            CompareNaturalNum = 1
            Exit Function
        End If
    End If
End Function

Function isDigit(ByVal str As String, pos As Integer) As Boolean
Dim iCode As Integer
    If pos <= Len(str) Then
        iCode = Asc(Mid(str, pos, 1))
        If iCode >= 48 And iCode <= 57 Then isDigit = True
    End If
End Function