注意：下面出现的“考生文件夹”均为c：\wexam\25160001。
在考生文件夹下有工程文件sjt5.vbp及窗体文件sjt5.frm，该程序是不完整的，请在有号的地方填入正确内容，然后删除及所有注释符(即’号)，但不能修改其他部分。存盘时不得改变文件名和文件夹。
本题描述如下：在名称为Form1的窗体上有三个Label控件和两个名称分别为COMSTART、 COMEXIT，标题分别为“开始”和“退出”的命令按钮。编写函数Item(A，N)，其功能是由数字A组成的不多于N位数的整数，利用该函数求8888-888-88-8的值并把结果写入考生文件夹下的sjt5.dat文件中。执行完毕“确定”按钮，变成“完成”，且无效。如图10-6所示。
参考答案： 控件是否可用由其Enable属性设置，当Enable为True时控件可用，当Enable为False时控件不可用(灰色)：命令按钮的标题由Caption属性设置：Str$函数将数字转换为字符串。解题步骤：
第一步：建立界面并设置控件属性。程序中用到的控件及其属性值见表A0-D。
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程序提供的代码：
Option Explicit
Private Sub COMEXIT_Click()
End
End Sub
Private Sub COMSTART_Click()
Dim A As Integer, N As Integer, J As Integer, Sum As Single
A= H: N= D
For J = N To A Step -A
If J = N Then
Sum = Item (A, J)
Else
Sum = Sum - Item(A, J)
End If
Next
Print "Sum="; Sum
Open App. Path & "\" & "sjtE.dat" For Output As #A
Print #A, Sum
Close #A
’.Caption = "完成"
’COMSTART. = False
End Sub
Function Item(A, k)
Dim P As String, Q As String, S As Single
Dim i As Integer, H As Single
p = ""
For i = A To k
Q$ =Str$ (A)
p$ = p$ + Q$
Next i
’ = Val(P$)
’H = + S
Item = H
End Function
参考代码:
Option Explicit
Private Sub COMEXIT_Click()
End
End Sub
Private Sub COMSTART_Click()
Dim A As Integer, N As Integer, J As Integer, Sum As Single
A= H: N = D
For J = N To A Step -A
If J = N Then
Sum = Item(A, J)
Else
Sum = Sum - Item(A, J)
End If
Next
Print "Sum="; Sum
Open App. Path & "\" & "sjtE.dat" For Output As #A
Print #A, Sum
Close #A
COMSTART.Caption = "完成"
COMSTART.Enabled = False
End Sub
Function Item(A, k)
Dim P As String, Q As String, S As Single
Dim i As Integer, H As Single
p = ""
For i = A To k
Q$ = Str$ (A)
P$ = P$ + Q$
Next i
S = Val (P$)
H = H + S
Item = H
End Function
第二步：调试并运行程序。
第三步：按题目要求存盘。