第5章习题
一、单选题
1．A 2. B 3．(1)C，(2)B
4．B 5．C 6．A
7．(1)B，(2)C，(3)B
8. B 9. B 10. B
二、填空题
1．(1)4次，n=13 (2)3次，n=8 (3)3次，n=27 (4)3次，n=10 (5)1次，n=12
2．(1) Len(s) (2) Mid(s, k, 1) (3) c + t (4) Text2.Text
3．(1) t = 1 (2) n = n + 1 (3) t = t * 2
4. 0
5. Text
6. 下拉列表框
7. AddItem ，RemoveItem或Clear
8．(1)ItemA (2) ItemD (3) ItemD (4) ItemA
9．(1) Mid(x, p + 3) (2) p + 4 (3) InStr(p, x, "123")
编程及上机调试
1. 和数为：1.21。程序代码如下：
Private Sub Form_Load()
Show
s = 0
For k = 1 To 100
s = s + 1 / (1 + k * 4)
Next k
Print s
End Sub
2. 程序代码如下：
Private Sub Form_Load()
Dim i As Integer, a As Integer, b As Integer, c As Integer
Show
For i = 100 To 999
a = Int(i / 100)
b = Int((i - 100 * a) / 10)
c = i - 100 * a - 10 * b
If a * a * a + b * b * b + c * c * c = i Then
Print i
End If
Next i
End Sub
3. 在窗体上建立一个文本框Text1(初始值)、一个列表框List1(显示结果)和一个命令按钮Comd1(“查找”)。
Private Sub Comd1_Click() '“查找”
Dim n As Integer
n = Val(Text1.Text)
List1.Clear:k = 0
Do While k <= 99
If Not (n Mod 7 = 0) Then
List1.AddItem n
k = k + 1
End If
n = n + 1
Loop
End Sub
4. 程序代码如下：
Private Sub Form_Load()
Show
n = Val(InputBox("正整数n="))
For i = 1 To n
For j = i + 1 To n
For k = j + 1 To n
If i * i + j * j = k * k Then
Print "("; i; ","; j; ","; k; ")"
End If
Next k
Next j
Next i
End Sub
5．在窗体上建立一个列表框List1和一个“显示表项”命令按钮Command1。程序代码如下：
Private Sub Command1_click() '"显示表项"按钮单击事件
FontSize = 12
Cls
For i = 0 To List1.ListCount - 1 '逐项判断
If List1.Selected(i) Then '真时为选中
Print List1.List(i)
End If
Next i
End Sub
6．(1) Text1.Text (2) UCase(x) (3) t >= "A" And t <= "Z" (4) y + x
7．程序代码如下：
Private Sub Form_Load()
Show
Dim a As Single, xn0 As Single, xn1 As Single
a = Val(InputBox("请输入一个正数"))
xn1 = a
Do
xn0 = xn1
xn1 = (xn0 + a / xn0) / 2
Loop While Abs(xn0 - xn1) >= 0.00001
Print a; "的平方根为"; xn1
End Sub
