16.小明設計了一個VB程序(界面如圖所示),隨機產生n(n<=100)個大于等于a(a<=100)且小于等于b(b<=100)的整數,并在列表框List1中降序顯示. 實現上述功能的VB代碼如下: 請在橫線處填入合適代碼. Private Sub Command1_Click( )Dim a As Integer,b As Integer Dim n As Integer,t As Integer Dim m(1To 100)As Integer a=Val(Text1.Text) b=Val(Text2.Text) n=Val(Text3.Text) If a>b Then t=a:a=b:b=t Randomize ①
For i=2To n m(i)=Int(Rnd*(b-a+1))+a If m(i)>m(i-1)Then ②
For j=i-1To 1Step-1 If temp<m(j) Then Exit For m(j+1)=m(j) Next j ③
End If Next i For i=1To n List1.AddItem Str(m(i)) Next i End Sub 程序①處的代碼是
17.編寫VB程序,實現如下功能:單擊“生成密文”按鈕Command2,在文本框Text3中產生與每個小寫字母對應的密文(每個明文字母對應1個不重復的密文字母).在文本框Text1中輸入單詞字符串,單擊“加密”按鈕Command1后,進行逐個字符加密,加密方法:在“明文”中找到相應字符,再得到明文對應位置的密文,并在文本框Text2中顯示對應密文(運行效果如圖所示).實現上述功能的VB代碼如下: Dim m2As String Private Sub Command1_Click
Dim flag(1To 26)As Boolean Dim num As Integer,t As Integer Randomize num=1 Text3.Text=““ For i=1To 26 flag(i)=False Next i Do While num<=26 x=Int(Rnd*26)+97 ①
If flag(t)=False Then m2=m2+Chr(x) num=num+1 ② End If Loop Text3.Text=m2 End Sub Private Sub Command2_Click
Dim s As String,m As String,result As String Dim k As String,c As Integer s=Text1.Text m=“abcdefghijklmnopqrstuvwxyz“ For i=1To Len(s) k=Mid(s,i,1) If k>=“A“And k<=“Z“Then k=Chr(Asc(k)+32) End If c=1:continue=True Do While③ If k=Mid(m,c,1)Then continue=False End If c=c+1 Loop ④ Next i Text2.Text=result End Sub 程序①處的代碼是