Excel VBA code (technical index for trading system)

Sub V()

'''-----http://www.samurai-logic.com/
'''-----Project of Trading System Development
'''------------------------------------------------------------------
''----Ｂ列（日付）、Ｃ列（始値）、Ｄ列（高値）、Ｅ列（安値）、Ｆ列（終値）
''----TextBox1に期間1、TextBox2に期間2
''--------------------------------------------------------------------
Dim length1%, length2%, length3%, LastRow&, i&, j%, j2&, Temp!

Application.ScreenUpdating = False
 
Worksheets("ボラティリティ").Activate
    
Range("H5:I5000").ClearContents
  
LastRow = Range("B4").End(xlDown).Row

length1 = CInt(ActiveSheet.TextBox1.Value)
length2 = CInt(ActiveSheet.TextBox2.Value)

Range("H3") = "Volatility:" & length1
Range("I3") = "Volatility:" & length2



For i = length1 + 5 To LastRow
 Temp = (WorksheetFunction.Max(CSng(Range("D" & i).Value) - _
        CSng(Range("F" & i - 1).Value), _
        CSng(Range("F" & i - 1).Value) - _
        CSng(Range("E" & i).Value), _
        CSng(Range("D" & i).Value) - _
        CSng(Range("E" & i).Value))) * 100
 
 If i = length1 + 5 Then
   Cells(i, 8).Value = _
   (Temp / WorksheetFunction.Average(Range("D" & i, "F" & i).Value))
   
 Else
   Cells(i, 8).Value = _
   CSng(Cells(i - 1, 8).Value) + _
   ((Temp / CSng(WorksheetFunction.Average(Range("D" & i, "F" & i).Value)) - _
   CSng(Cells(i - 1, 8).Value)) * 2 / (1 + length1))
 End If
 
  If i = length2 + 5 Then
    Cells(i, 9).Value = _
    (Temp / CSng(WorksheetFunction.Average(Range("D" & i, "F" & i).Value)))
  ElseIf i > (length2) + 5 Then
    Cells(i, 9).Value = CSng(Cells(i - 1, 9).Value) + _
    ((Temp / CSng(WorksheetFunction.Average(Range("D" & i, "F" & i).Value)) - _
    CSng(Cells(i - 1, 9).Value)) * 2 / (1 + length2))
  End If

Next

Range("H5", "I" & LastRow).NumberFormatLocal = "0.00"
Application.ScreenUpdating = True
End Sub