ฟังก์ชัน SYD

Dim Fmt, InitCost, SalvageVal, MonthLife, LifeTime, DepYear, PDepr
Const YEARMONTHS = 12    ' Number of months in a year.
Fmt = "###,##0.00"    ' Define money format.
InitCost = InputBox("What's the initial cost of the asset?")
SalvageVal = InputBox("What's the asset's value at the end of its life?")
MonthLife = InputBox("What's the asset's useful life in months?")
Do While MonthLife < YEARMONTHS    ' Ensure period is >= 1 year.
    MsgBox "Asset life must be a year or more."
    MonthLife = InputBox("What's the asset's useful life in months?")
Loop
LifeTime = MonthLife / YEARMONTHS    ' Convert months to years.
If LifeTime <> Int(MonthLife / YEARMONTHS) Then
    LifeTime = Int(LifeTime + 1)    ' Round up to nearest year.
End If 
DepYear = CInt(InputBox("For which year do you want depreciation?"))
Do While DepYear < 1 Or DepYear > LifeTime
    MsgBox "You must enter at least 1 but not more than " & LifeTime
    DepYear = CInt(InputBox("For what year do you want depreciation?"))
Loop
PDepr = SYD(InitCost, SalvageVal, LifeTime, DepYear)
MsgBox "The depreciation for year " & DepYear & " is " & Format(PDepr, Fmt) & "."