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