Option Explicit
'源泉所得税クラス
'プロパティはメンバー以外アクセスできない

'プロパティの実体
Private mdblZei As Double           '源泉所得税
Private mdblKyuyoKoujo As Double    '給与所得控除後の金額
Private mdblFuyouKoujo As Double    '扶養控除

Public Property Get Zei() As Double

    Zei = mdblZei
    
End Property

Public Property Let Zei(ByVal dblZei As Double)

    mdnlzei = dblZei
    
End Property

Public Sub CalculateZei(ByVal lngKazei As Long, ByVal intNinzu As Integer)

'引数[lngKazei]：社会保険控除後の課税所得
'引数[intNinzu]：扶養親族数

    Call KyuyoKoujo(lngKazei)
    Call FuyouKoujo(intNinzu)
    Call GensenZei(lngKazei, CLng(mdblKyuyoKoujo), CLng(mdblFuyouKoujo))
    
End Sub


'----------  給与の源泉所得税計算の一連作業  ----------

'給与所得控除額の計算
Private Sub KyuyoKoujo(ByVal lngKyuyo As Long)

'引数[ingKingaku]：社会保険料控除後の給与額

    Const dblKiriage As Double = 0.9    '切り上げ定数
    
    Select Case lngKyuyo
        Case Is <= 135416
            mdblKyuyoKoujo = CDbl(54167)
        Case lngKyuyo = 135417 To 149999
            mdblKyuyoKoujo = Int(CDbl(lngKyuyo * 0.4 + dblKiriage))
        Case lngKyuyo = 150000 To 299999
            mdblKyuyoKoujo = Int(CDbl((lngKyuyo * 0.3) + 15000 + dblKiriage))
        Case lngKyuyo = 300000 To 549999
            mdblKyuyoKoujo = Int(CDbl((lngKyuyo * 0.2) + 45000 + dblKiriage))
        Case lngKyuyo = 550000 To 833333
            mdblKyuyoKoujo = Int(CDbl((lngKyuyo * 0.1) + 100000 + dblKiriage))
        Case Is >= 833333
            mdblKyuyoKoujo = (lngKyuyo * 0.05) + 141667
        Case Else
            mdblKyuyoKoujo = CDbl(0)
    End Select
    
End Sub

'基礎控除等の計算
Private Sub FuyouKoujo(ByVal lngNinzu As Integer)

'引数[intNinzu]：扶養家族の人数

    Const lngKiso As Long = 1       '基礎控除
    Const lngGaku As Long = 31667   '基礎控除額
    
    mdblFuyouKoujo = CDbl(lngGaku * (lngKiso + lngNinzu))
    
End Sub

'源泉所得税額の計算
Private Sub GensenZei(ByVal lngKazei As Long, ByVal lngKoujo1 As Long, ByVal lngKoujo2 As Long)

'引数[lngKazei]：課税所得
'引数[lngKoujo1]：給与所得控除
'引数[lngKoujo2]：扶養控除

    Dim lngHyoujun As Long          '課税標準
    Const intKeta As Integer = 10   '四捨五入桁数
    Const dblRound As Double = 0.5  '四捨五入定数
    
    lngHyoujun = lngKazei - (lngKoujo1 + lngKoujo2)
    
    Select Case lngHyoujun
        Case lngHyoujun = 0 To 275000
            mdblZei = Int(CDbl((lngHyoujun * 0.08) / intKeta + dblRound)) * intKeta
        Case lngHyoujun = 275001 To 658334
            mdblZei = Int(CDbl((lngHyoujun * 0.16 - 22000) / intKeta + dblRound)) * intKeta
        Case lngHyoujun = 658335 To 750000
            mdblZei = Int(CDbl((lngHyoujun * 0.2 - 48334) / intKeta + dblRound)) * intKeta
        Case lngHyoujun = 750001 To 1500000
            mdblZei = Int(CDbl((lngHyoujun * 0.3 - 123334) / intKeta + dblRound)) * intKeta
        Case Is >= 1500001
            mdblZei = Int(CDbl((lngHyoujun * 0.37 - 228334) / intKeta + dblRound)) * intKeta
        Case Else
            mdblZei = CDbl(0)
    End Select
    
End Sub