' Indexed ShellSort of an array of any type'' Indexed Sorts are sort procedures that sort an index array' instead of the main array. You can then list the items in' sorted member by simply scanning the index, as in'   For i = 1 To numEls: Print arr(ndx(i)): Next'' NUMELS is the index of the last item to be sorted, and is' useful if the array is only partially filled.'' Works with any kind of array, except UDTs and fixed-length' strings, and including objects if your are sorting on their' default property. String are sorted in case-sensitive mode.'' You can write faster procedures if you modify the first two lines' to account for a specific data type, eg.' Sub NdxShellSortS(arr() As Single, ndx() As Long,'  '   Optional numEls As Variant, Optional descending As Boolean)'   Dim value As SingleSub NdxShellSort(arr As Variant, ndx() As Long, Optional numEls As Variant, _    Optional descending As Boolean)    Dim value As Variant    Dim index As Long, index2 As Long    Dim firstItem As Long    Dim distance As Long    Dim tempNdx As Long    ' account for optional arguments    If IsMissing(numEls) Then numEls = UBound(arr)    firstItem = LBound(arr)    ' init index array if necessary    If ndx(firstItem) = 0 And ndx(UBound(ndx)) = 0 Then        For index = firstItem To UBound(ndx)            ndx(index) = index        Next    End If        ' find the best value for distance    Do        distance = distance * 3 + 1    Loop Until distance > numEls        Do        distance = distance  3        For index = distance + 1 To numEls            tempNdx = ndx(index)            value = arr(tempNdx)            index2 = index            Do While (arr(ndx(index2 - distance)) > value) Xor descending                ndx(index2) = ndx(index2 - distance)                index2 = index2 - distance                If index2 <= distance Then Exit Do            Loop            ndx(index2) = tempNdx        Next    Loop Until distance = 1End Sub