vb代码——计算器.doc

第三题 Option ExplicitPrivate StoredValue As Double 中间计算值Private Store1 As DoublePrivate Const opNone = 0 代表没有运算符Private Const opAdd = 1 代表加法常量Private Const opSubtract = 2 代表减法常量Private Const opMultiply = 3 代表乘法常量Private Const opDivide = 4 代表除法常量Private Operator As Integer 计算符号 因子Private NewEntry As Boolean 新数据项逻辑变量,若为True，说明无新数据Private jscs As IntegerPrivate Const pi = 3.1415926Private Sub CmdBack_Click() 删除最后一个字符. Dim txt As String Dim min_len As Integer txt = txtDisplay.Text If Left$(txt, 1) = - Then 假如txt中的第一个字符是负号，只有两个字符，删除就会使之为0 min_len = 2 Else 假如txt是正数，只有一个字符，删除就会使之为0 min_len = 1 End If If Len(txt) min_len Then txtDisplay.Text = Left$(txt, Len(txt) - 1) Else txtDisplay.Text = 0 End IfEnd SubPrivate Sub CmdCal_Click(Index As Integer) Select Case Index Case 0 Operator = opAdd Case 1 Operator = opSubtract Case 2 Operator = opMultiply Case 3 Operator = opDivide End Select NewEntry=True 这种方法正确，但显得比较烦琐，下面的方法显得更为简单,不但调用了CmdEqual_Click程序 且运算符号可以直接计算 jscs = jscs + 1 If jscs 1 Then 执行前面的操作 cmdEqual_Click End If 存储操作符 Operator = Index + 1 开始新数据. NewEntry = True End SubPrivate Sub cmdClear_Click() cmdClearEntry_Click StoredValue = 0 jscs = 0 Operator = opNoneEnd SubPrivate Sub cmdClearEntry_Click() txtDisplay.Text = 0End SubPrivate Sub cmdNum_Click(Index As Integer) If NewEntry Then txtDisplay.Text = Format$(Index) NewEntry = False Else If txtDisplay.Text = 0 Then txtDisplay.Text = Format$(Index) Else txtDisplay.Text = txtDisplay.Text & Format$(Index) End If End IfEnd SubPrivate Sub cmdOFF_Click() Unload MeEnd SubPrivate Sub cmdPn_Click() 正负键输入 If NewEntry Then 假如是新数据，则敲+/-键为负号 txtDisplay.Text = - ElseIf Left$(txtDisplay.Text, 1) = - Then 假若数据本身为负值，则按此键变为正值 txtDisplay.Text = Right$(txtDisplay.Text, 2) Else txtDisplay.Text = - & txtDisplay.Text 若数据为正值，则转化为负值 End IfEnd SubPrivate Sub cmdDecimal_Click() 小数点输入 If InStr(txtDisplay.Text, .) Then 若数据中已有小数点，则发出Beep的声音 Beep Else If NewEntry Then txtDisplay.Text = . 若为新数据，则直接输入小数点，数据变为旧数据 NewEntry = False Else txtDisplay.Text = txtDisplay.Text & . 若为旧数据，则将以前数据与小数点相连 End If End IfEnd Sub 计算上述计算操作的结果Private Sub cmdEqual_Click() Dim new_value As Double If txtDisplay.Text = Then 若数据框中无数据则为，否则将该数转换为双精度数 new_value = 0 Else new_value = CDbl(txtDisplay.Text) End If Select Case Operator Case opNone StoredValue = new_value Case opAdd StoredValue = StoredValue + new_value Case opSubtract StoredValue = StoredValue - new_value Case opMultiply StoredValue = StoredValue * new_value Case opDivide StoredValue = StoredValue / new_value End Select Operator = opNone NewEntry = True txtDisplay.Text = StoredValue txtResult.Text = Format$(StoredValue) End SubPrivate Sub CmdStorage_Click(Index As Integer) Select Case Index Case 0 Store1 = Store1 + CDbl(txtDisplay.Text) NewEntry = True If Store1 0 Then txtM.Visible = True Else txtM.Visible = False Case 1 txtDisplay.Text = CStr(Store1) If Store1 0 Then txtM.Visible = True Else txtM.Visible = False MsgBox 寄存器中的数据为 & txtDisplay.Text Case 2 Store1 = 0 txtDisplay.Text = 0 MsgBox 寄存器中的数据已清0 txtM.Visible = False End Select End SubPrivate Sub cmdTransfer_Click() frmTransfer.Show 1End SubPrivate Sub Command1_Click(Index As Integer) Dim Result As Double, angle As Single, x As Double If txtDisplay.Text = Then MsgBox 请输入数据: Exit Sub NewEntry = True Select Case Index Case 0 求正弦，输入角度单位为度 angle = CDbl(txtDisplay) * pi / 180 Result = Sin(angle) txtDisplay = Format(Result, #0.#) Case 1 求余弦，输入角度单位为度 angle = CDbl(txtDisplay) * pi / 180 Result = Cos(angle) txtDisplay = Format(Result, #0.#) Case 2 求正切，输入角度单位为度 angle = CDbl(txtDisplay) * pi / 180 Result = Tan(angle) txtDisplay = Format(Result, #0.#) Case 3 求余切，输入角度单位为度 angle = CDbl(txtDisplay) * pi / 180 Result = 1 / Tan(angle) txtDisplay = Format(Result, #0.#) Case 4 求反正弦 If Val(txtDisplay.Text) 1 Or Val(txtDisplay.Text) 1 Or Val(txtDisplay.Text) 12 Then MsgBox 所输入的整数太大，其阶乘超出长整型范围。 txtDisplay.Text = 0 txtDisplay.SetFocus Exit Sub End If Result = Factor(n) txtDisplay = CStr(Result) Case 11 求自然对数 x = CDbl(txtDisplay.Text) If x 0 Then MsgBox 所输入的数不能为负，请重新输入。 txtDisplay.Text = 0 Exit Sub End If Result = Log(x) txtDisplay = Format(Result, #0