s1 = Text1.Text: s2 = Text2.Text
i = 1: j = 1
Do While i <= Len(s1) And j <= Len(s2)
If Mid(s1, i, 1) = Mid(s2, j, 1) Then 
Loop
If 
Then Label1.Caption = "是子串" Else Label1.Caption = "不是子串"
方框处的可选语句为：
①i = i + 1 ②j = j + 1 ③i > Len(s2) ④j > Len(s2)
以下选项正确的是（ ）
i=1: j=n
Do While i<=j
m=(i +j)\2
If 
Then
i= m+1
Else
j=m- 1
EndIf
Loop
Text1.Text=
若要实现上述功能，方框处的代码应是（ ）
图a
图b
图a
图b
编写如下VB程序，实现上述功能。运行程序，在文本框Text1中输入随机数列“19,21,3,5,18,18,18,23,25,10,11,12,17,17,7”，单击“统计”按钮，在文本框Text2中输出5。
程序运行界面如图所示。
Dim a(1 To 100) As Integer '数组a依次存放数列中的数Dim n As Integer
Private Sub Command1_Click( )
Dim i As Integer, k As Integer, max As Integer, t As Integer Dim s As String, ch As String
s = Text1.Text n = Len(s)
i = 1: k = 1
Do While i <= n
ch = Mid(s, i, 1)
If ch <> "," Then Else k = k + 1 i = i + 1
Loop
i = 1: max = 0
Do While i <= k
t =
If t > max Then max = t i = i + t
Loop
Text2.Text = Str(max)
End Sub
Function length(p As Integer) As Integer '函数功能是计算a(p)开始的非降序段长度
Dim j As Integer, c As Integer
j = p: c = 1
Do While j <= n – 1
If 
Then
If a(j) < a(j + 1) Then c = c + 1 Else
Exit Do
End If
j = j + 1
Loop
length = c
End Function
Dim yf(1 To 10) As Integer, v(1 To 10) As Integer, b(1 To 10) As Integer
Private Sub Command1_Click()
Dim n As Integer, i As Integer, j As Integer, t As Integer
List1.AddItem "船只编号" + " " + "载重量" + " " + "运费单价" List2.AddItem "船只编号"
For i = 1 To 10 '对船只进行编号
b(i) = i
Next i
'随机生成10艘船的运费单价，数值在100到200之间，代码略
For i = 1 To 10 '随机生成10艘船载重量，载重量均不相同
v(i) = 15 + Int(Rnd() * 16)
For j = 1 To i - 1
If v(i) = v(j) Then : Exit For
Next j
Next i
For i = 1 To 9
For j = 10 To i + 1 Step -1
If Then
t = b(j): b(j) = b(j - 1): b(j - 1) = t
End If
Next j
Next i
'在list1中输出10艘船的编号、载重量、运费单价，代码略
End Sub
Private Sub Command2_Click()
Dim n As Integer, k As Integer
Dim sum As Long
n = Val(Text1.Text): sum = 0 k = 1
Do While n > 0
If n >= v(b(k)) Then
Else
sum = sum + n * yf(b(k))
End If
List2.AddItem Str(b(k)) n = n - v(b(k))
k = k + 1
Loop
Text2.Text = Str(sum)
End Sub
