代码如下：

/**

*Author:乌鸟heart

*Version:1.0

*/

Dim IntX As Double '全局变量，用于存储计算的数值

Dim IntOperation As Double '标记运算类型

Dim isBegin As Boolean '标记是否已经给IntX赋值

Public Sub Clear() '清空命令函数

screen.Caption = ""

End Sub

Public Sub SavaToIntX()

Select Case IntOperation

Case 1 '加法

If isBegin = False Then

IntX = Val(screen.Caption)

isBegin = True

Else

IntX = IntX + Val(screen.Caption)

End If

Case 2 '减法

If isBegin = False Then

IntX = Val(screen.Caption)

isBegin = True

Else

IntX = IntX - Val(screen.Caption)

End If

Case 3 '乘法

If isBegin = False Then

IntX = Val(screen.Caption)

isBegin = True

Else

IntX = IntX * Val(screen.Caption)

'screen.Caption = IntX

End If

Case 4 '除法

If isBegin = False Then

IntX = Val(screen.Caption)

isBegin = True

Else

IntX = IntX / Val(screen.Caption)

End If

End Select

End Sub

Private Sub Command0_Click()

screen.Caption = screen.Caption & 0

End Sub

Private Sub Command1_Click()

screen.Caption = screen.Caption & 1

End Sub

Private Sub Command2_Click()

screen.Caption = screen.Caption & 2

End Sub

Private Sub Command3_Click()

screen.Caption = screen.Caption & 3

End Sub

Private Sub Command4_Click()

screen.Caption = screen.Caption & 4

End Sub

Private Sub Command5_Click()

screen.Caption = screen.Caption & 5

End Sub

Private Sub Command6_Click()

screen.Caption = screen.Caption & 6

End Sub

Private Sub Command7_Click()

screen.Caption = screen.Caption & 7

End Sub

Private Sub Command8_Click()

screen.Caption = screen.Caption & 8

End Sub

Private Sub Command9_Click()

screen.Caption = screen.Caption & 9

End Sub

Private Sub CommandClear_Click() '清空命令

isBegin = False

IntOperation = 0

IntX = 0

screen.Caption = ""

End Sub

Private Sub CommandEqual_Click() '等号运算

If IntOperation <> 0 Then '有运算标记的情况

Call SavaToIntX

IntOperation = 0

isBegin = False

screen.Caption = IntX

End If

End Sub

Private Sub CommandMinus_Click() '减法运算

If IntOperation <> 0 Then '有运算标记的情况

Call SavaToIntX

IntOperation = 2

Call Clear

Else

IntOperation = 2

Call SavaToIntX

Call Clear

End If

End Sub

Private Sub CommandMultiple_Click() '乘法运算

If IntOperation <> 0 Then '有运算标记的情况

Call SavaToIntX

IntOperation = 3

Call Clear

Else

IntOperation = 3

Call SavaToIntX

Call Clear

End If

End Sub

Private Sub CommandPlus_Click() '加法运算

If IntOperation <> 0 Then '有运算标记的情况

Call SavaToIntX

IntOperation = 1

Call Clear

Else

IntOperation = 1

Call SavaToIntX

Call Clear

End If

End Sub

Private Sub CommandSlash_Click() '除法运算

If IntOperation <> 0 Then '有运算标记的情况

Call SavaToIntX

IntOperation = 4

Call Clear

Else

IntOperation = 4

Call SavaToIntX

Call Clear

End If

End Sub