小林编写了一个用于1至9之间整数加减乘除运算的小程序,具体功能如下:在文本框 Text1中输入一个算术表达式(该表达式仅包含1至9之间的整数和加减乘除运算符,其中最后一个运算符肯定是乘或除,且乘或除运算符的前和后一个运算符仅可能为加减或没有),单击“计算”按钮Command1,将运算结果显示在 Label2中。程序运行界面如图所示,实现上述功能的VB程序如下,请回答下列问题:

(1)将窗体标题更改为“简单算术运算”,应修改窗体的________________属性的属性值。
(2)请在划线处填入合适的代码。
(3)加框处的代码有错误,请改正。
Private Sub Commandl_ Click()
Dim s As String, c As String, i As Integer
Dim sum As Single, suml As Single, sum2 As Single, k As Integer, j As Integer
s= Text1. Text: sum2= 0:k=1
For i= I To Len(s)
c= ____________________
If c=“*” Or c=“/”Then
If c=“*” Then
sum= Val (Mid (s, i+ 1. 1)* Val (Mid (s, i- 1, 1))
Else
sum= Val (Mid (s, i- 1,1)/Val (Mid (s, i+ 1, 1))
End If
j= i-2
Do While

________
c= Mid(s, j, D)
If c=“+” Then suml- Val (Mid (s, j- l, 1))+sum
If c=“-” Then suml – Val (Mid (s, j-1, i))-sum
sum= sum1
j= j- 1
Loop
If k= 1 Then
sum2= sum2 + sum
Else
c= Mid(s, k, 1)
If c=“+”Then sum2= sum2 + sum
If c=“-”Then sum2= sum2- sum
End If
k= _________________
End If
sum = 0
Next i
Label2. Caption=sum2
End Sub