实现上述功能的VB代码如下, 但划线处代码有错，请改正。

Dim a(1 To 50) As Integer

Private Sub Command1_Click()

Dim i As Integer

k = 0: i = 3

Do While i <= 100

   If  ① prime(i)   Then      ‘⑴

      k = k + 1

      a(k) = i

   End If  

   i = i + 2

Loop

For i = 2 To k

   If   ②a(i) = a(i +1)+2   Then   ‘⑵

      List1.AddItem Str(a(i - 1)) + "和" + Str(a(i))

   End If

Next i

End Sub

Function prime(x As Integer) As Boolean

prime = False

For i = 2 To Int(Sqr(x))

   If  x Mod i = 0  Then

      prime = True

      Exit For

   End If

Next i

End Function

① {#blank#}1{#/blank#}  ②{#blank#}2{#/blank#}  

k = 0                                 '用来计数

Max = Val(Text1.Text)                   '指定范围

n = 9                            '①

Do While n <= Max                    

  If n Mod 3 = 2 And n Mod 5 = 3 Then  '②

     List1.AddItem Str(n)            

  End If                            

  n = n + 7        ' ③

  k = k + 1         ④

Loop

Label1.Caption = Str(Max) & "范围内满足问题的数有" & Str(k) & "个"

运行程序，在文本框中输入自然数600，结果统计的个数与列表框中输出的个数不相符，如图所示：

请问出现此问题的原因是  (    )

n = Len(s)  's是判断的字符串

  k = 0: j = n

  For i = 1 To n \ 2

  Next i

  If k = 0 Then Label1.Caption = "对称" Else Label1.Caption = "不对称"

方框中的代码由以下三部分组成：

①j = j - 1

②If c1< >c2 Then k = k + 1

③c1 = Mid(s,i,1) : c2 = Mid(s,j,1)

代码顺序正确的是（  ）

Dim a(1 To 1000) As Integer

Dim n As Integer

Private Sub Form_Load()

‘确定n的值和数组a的各个元素值，即每根棍子的长度值，代码略

End Sub

Function max(x As Integer, y As Integer) As Integer

If x > y Then

    max=x

  Else

    max=y

  End If

End Function

Private Sub Command1_Click()

  Dim i As Integer , j As Integer , k As Integer

  Dim ans As Integer , c As Integer , longest As Integer , rest As Integer

ans=0

  ‘让 i<j<k,保证棍子不会重复选中

  For i=1 To n

  For j=i+1 To n

   For k=j+1 To n

    c=a(i)+a(j)+a(k)

    longest=     ‘①

    rest=c-longest    ‘rest 保存最短的两条边的和

    If  Then    ‘②

     ans=max(ans , c)

End If

   Next k

Next j

  Next i

Print ans

End Sub

①{#blank#}1{#/blank#} ②{#blank#}2{#/blank#} 

最佳方案:初始时所有人聚集在2号房间，花费的能量和:7*0+8*1+6*2+4*3+4*4=48。为了解决这个问题，小明编写了一个VB程序。在窗体加载时，从数据库中读取N的值和编号为1到N的房间的居住人数，人数存储在数组a中。点击窗体上的按钮Command1，程序枚举每一种方案(不同的初始房间)，计算该方案的能量和，在文本框Text1中输出最优方案的初始房间编号，在文本框Text2中输出最小能量和。

实现上述功能的VB代码如下，请在划线处填入合适代码。

Dim a(1 To 100) As Integer ’依次存储编号为1到100的房间的居住人数

Private Sub Form_Load()

‘本过程从数据库中读取N的值和每个房间居住人数，存储在数组a中

‘代码略

End Sub

Private Sub Command1_Click()

Dim i As Integer, j As Integer, w As Integer, k as Integer

Dim t As Long, ans As Long

k=0 : ans = 32767     ‘ans初始化为最大的Integer数据

For i = 1 To n

 t = 0

 For j = 0 To n - 1

    w={#blank#}1{#/blank#}

    If w = 0 Then w = n

    t={#blank#}2{#/blank#}

 Next j

 If t < ans Then

    k= i

    ans = t

 End If

Next i

Text1.Text = Str (k)    ‘起始房间编号

Text2.Text ={#blank#}3{#/blank#}

End Sub

实现上述功能的VB代码如下。

Dim a(1 To 50) As Integer

Private sub Command1_Click()

    Dim i As Integer

    k=0: i=3

    Do While i<= 100

        If Not prime(i) Then

            k=k+1

        End If

        i=i+2

    Loop

    For i=2 To k

        If         Then

            List1 AddItem Str(a(i-1))+"和"+ Str(a(i))

        End if

    Next i

End Sub

Function prime (x As Integer)As Boolean

    prime=False

    For i=2 To Int(sar(x))

        If x Mod i=0 Then

            prime=True

            Exit for

        End If

    Next i

End Function