1. (2020·浙江模拟) 编写VB程序，实现如下功能：单击“生成密文”按钮Command2，在文本框Text3中产生与每个小写字母对应的密文(每个明文字母对应1个不重复的密文字母)。在文本框Text1中输入单词字符串，单击“加密”按钮Command1后，进行逐个字符加密，加密方法：在“明文”中找到相应字符，再得到明文对应位置的密文，并在文本框Text2中显示对应密文(运行效果如图所示)。实现上述功能的VB代码如下，请完善程序代码。

Dim m2 As String

Private Sub Command1_Click()

Dim flag(1 To 26) As Boolean

Dim num As Integer，t As Integer

Randomize

num = 1

Text3.Text = “”

For i = 1 To 26

 flag(i) = False

Next i

Do While num <= 26

 x = Int(Rnd * 26) + 97

 

 If flag(t) = False Then

m2 = m2 + Chr(x)

num = num + 1

 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 = 1 To 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 While

If k = Mid(m, c, 1) Then

 continue = False

End If

c = c + 1

 Loop

 

Next i

Text2.Text = result

End Sub