填补空白

Sub FillTransactions()
    
    ' Read.
    
    Dim ws As Worksheet: Set ws = ActiveSheet ' improve!
    
    Dim rCount As Long: rCount = ws.UsedRange.Rows.Count - 1
    If rCount < 2 Then Exit Sub
    
    Dim rg As Range: Set rg = ws.Range("A2").Resize(rCount)
    
    Dim Data() As Variant: Data = rg.Value
    
    ' Modify.
    
    Dim r As Long, OldNum As Long, NewNum As Long
    
    For r = 1 To rCount
        NewNum = Data(r, 1)
        If NewNum = 0 Then Data(r, 1) = OldNum Else OldNum = NewNum
    Next r
    
    ' Write.
    
    rg.Value = Data

End Sub