程序界面如下图所示,程序运行时,在文本框Text1中输入一段文本,在文本框Text2中输入查找的字符串,在文本框Text3中输入替换为的字符串,单击“查找替换”按钮Command1,则在文本框Text4中输出替换后的文本,在标签Label6中显示替换的次数。
实现上述功能的VB程序如下,请在程序划线处填入合适的代码。
Private Sub Command1_Click()
Dim st1 As String, st2 As String
Dim i As Integer, n As Integer, count As Integer
Dim st3 As String, ch As String, result As String
result = “ ”
st1 = Text1.Text
st2 = Text2.Text
st3 = Text3.Text
len1 = Len(Text2.Text)
result = “ ”
i = 1
Do While i <= n
If ch = st2 Then
result = result + st3
count = count + 1
i = i + len1
Else
i = i + 1
End If
Loop
Text4.Text = result
Label6.Caption = Str(count)
End Sub
key = Val(Text1.Text)
i = 1: j = 10
Text2.Text = “ ”
Do While i <= j
m = Int((i + j) / 2 + 0.5)
If key = a(m) Then Exit Do 'Exit Do表示退出循环
If key < a(m) Then j = m - 1 Else i = m + 1
Text2.Text = Text2.Text + Str(a(m))
Loop
数组元素a(1)到a(10)的值依次为“8,17,24,30,36,40,55,58,61,66”,文本框Text1中输入的值是30,执行该程序段,文本框Text2中显示的是( )
Dim a As String, b As String, p As String, s As String
a = Text1.Text
b = Text2.Text
c = Text3.Text
p = “ ”
For i = 1 To Len(a)
If b = Mid(a, i, Len(b)) Then
s = s + c
p = p + Str(i)
Else
s = s + Mid(a, i, 1)
End If
Next i
Label1.Caption = p
若文本框Text1中输入“Hello,Python!I use Python!”,文本框Text2中输入“Python”, 文本框Text3中输入“VB”运行该段程序后,标签Label1中显示的是( )
为实现上述的功能的程序如下,加框处的代码有误,请改正。
Dim book(1 To 20) As String, st As String
Const n = 20
Private Sub Form_Load()
'读入n个数据,存储在数组book中,并显示在列表框List1中
End Sub
Private Sub Command1_Click()
Dim i As Integer, j As Integer, len1 As Integer, len2 As Integer,k As Integer
st = Text1.Text
List2.Clear
len1 = Len(st)
k = 0
For i = 1 To n
len2 = Len(book(i))
'①
Do While j <= len2 - len1 + 1
If Then '②
List2.AddItem book(i)
k = k + 1
End If
j = j + 1
Loop
Next i
If k> 0 Then
List2.AddItem “共找到”+Str(k) + “条信息”
Else
List2.AddItem “查无此书”
End If
End Sub
程序中加框①处应改正为;
加框②处应改正为。
i = 1: j = 10
Key = Val(Text1.Text)
Do While i <= j
m = (i + j) \ 2
If a(m) = Key Then Exit Do ′Exit Do表示退出循环
If Key Mod 2 = 1 And a(m) Mod 2 = 0 Then
ElseIf Key Mod 2 = 0 And a(m) Mod 2 = 1 Then
Else
End If
Loop
If i > j Then s = “没有找到!” Else s = “位置:” + Str(m)
Text2.Text = s
上述程序中方框处可选语句为:
①i = m + 1
②j = m - 1
③If Key < a(m) Then j = m - 1 Else i = m + 1
则(1)、(2)、(3)处语句依次是( )
flag=True
Key=Val(Text1.Text)
i=1
Do While i<=8 And flag
If a(i)=Key Then
flag=False
Else
i=i+1
End If
Loop
If Not flag Then
Label1.Caption=“Find!”
Else
Label1.Caption=“Fail!”
End If
数组元素a(1)到a(8)的数据依次为“11,2,0,6,8,3,5,8”,程序运行时,在文本框Text1中输入8,则在标签Label1中显示的内容是( )
i = 1: j = 7: s = “ ”
key = Int(Rnd * 100)
Do While i <= j
m = (i + j) \ 2
If key = a(m) Then
s = s + “M”: Exit Do 'Exit Do 表示退出循环
ElseIf key < a(m) Then
j = m - 1: s = s + “L”
Else
i = m + 1: s = s + “R”
End If
Loop
Text1.Text = s
数组元素a(1)到a(7)的值依次为“24,35,38,41,45,69,78”。若该程序段执行后,文本框Text1中显示的内容可能是( )