Public Sub QuickSortNonRecursive(SortArray() As oper)

    Dim i As Long, j As Long, lb As Long, ub As Long
    Dim stack() As QuickStack, stackpos As Long, ppos As Long, pivot As oper, swp As oper

    ReDim stack(1 To 1024)
    stackpos = 1

    stack(1).Low = LBound(SortArray)
    stack(1).High = UBound(SortArray)

    Do
        lb = stack(stackpos).Low
        ub = stack(stackpos).High
        stackpos = stackpos - 1
        Do
            ppos = (lb + ub) \ 2
            i = lb: j = ub: pivot = SortArray(ppos)

            Do
                Do While SortArray(i).dat < pivot.dat: i = i + 1: Loop
                Do While pivot.dat < SortArray(j).dat: j = j - 1: Loop
                If i <= j Then
                    swp = SortArray(i): SortArray(i) = SortArray(j): SortArray(j) = swp
                    i = i + 1
                    j = j - 1
                End If
            Loop While i <= j

            If i < ppos Then
                If i < ub Then
                    stackpos = stackpos + 1
                    stack(stackpos).Low = i
                    stack(stackpos).High = ub
                End If
                ub = j
            Else
                If j > lb Then
                    stackpos = stackpos + 1
                    stack(stackpos).Low = lb
                    stack(stackpos).High = j
                End If
                lb = i
            End If
        Loop While lb < ub
    Loop While stackpos
End Sub