第9章习题
单选题
1．B 2．D 3．D
4．B 5. A 6. A
编程及上机调试
1. 程序代码如下：
Private Sub Form_load()
Dim x(3) As Single, y As Single
On Error GoTo errln '以后出错时转移到errln
y = 2 / 0 '产生"除数为0"的错误
x(4) = 1 '产生"下标越界"的错误
MsgBox ("终止程序的运行")
Unload Me '卸载窗体
End
errln: '标号
Select Case Err.Number
Case 11 '"除数为0"的错误码为11
MsgBox ("除数为0(错误码为11)，跳过该错误")
Resume Next '返回
Case 9 '"下标越界"的错误码为9
MsgBox ("下标越界(错误码为9)，跳过该错误")
Resume Next '返回
Case Else '其他错误处理
MsgBox ("错误发生在" & Err.Source _
& ", 代码为" & Err.Number _
& ", 即" & Err.Description)
End Select
End Sub
2．改正后的程序代码如下：
Private Sub Form_Load()
Show
For i = 1 To 11
Print Tab(20 - i);
For j = 1 To 2 * i - 1
If j <= i Then
k = j
Else
k = 2 * i - j
End If
If k > 9 Then k = k + 7
Print Chr(k + 48);
Next j
Next i
End Sub
3．(1) n = n + 1 (2) d(1, j) = d(3, j) (3) d(i, 2) = d(i, 4)
(4) i = j Or i + j = 5 (5) d(i, j) = d(i, j) + 1
(6) n = 0 (7) Text1.Text
