VB工程--百例59--指数、对数函数计算器

Option Explicit

Private Sub cmd1_Click()
        If Val(txt1.Text) > 709 Then        若文本框txt1.中输入的数值大于709
           txt2.Text = "数值过大，请重新输入"则在txt2. 显示 "数值过大，请重新输入"
        Else      若文本框txt1输入的数值小于709
           txt2.Text = Exp(Val(txt1.Text))计算e^x的数值并在txt2只中输出结果
        End If
End Sub
Private Sub cmd2_Click()                          cmd2、cmd3、cmd4同理
        If Val(txt1.Text) > 308 Then
           txt2.Text = "数值过大，请重新输入"
        Else
           txt2.Text = 10 ^ (Val(txt1.Text))
        End If
End Sub

Private Sub cmd3_Click()
        If Val(txt1.Text) <= 0 Then
           txt2.Text = "不是有效数值！"
        Else
           txt2.Text = Log(Val(txt1.Text))
        End If
End Sub

Private Sub cmd4_Click()
        If Val(txt1.Text) <= 0 Then
           txt2.Text = "不是有效数值！"
        Else
          txt2.Text = Log(Val(txt1.Text)) / Log(10)
        End If
End Sub

Private Sub cmd5_Click()
        txt1.Text = ""
        txt2.Text = ""
End Sub

Private Sub cmd6_Click()
        End
End Sub

 

成品图