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用26个互不重复的ASCI字符作为密码本，根据英文字母在字母表中位置，替换为密码本该位置的字符。现编写将英文字母加密的VB程序，在文本框Text1中输入明文，单击“加密”按钮Command1，在文本框Text2、Text3中输出产生的密码本和密文。程序运行界面如下图所示。
                  
实现上述功能的VB代码如下，但加框处代码有错，请改正。
Private Sub Command1_Click()

Dim i As Integer, mw As String, jm As String

mw= Text1.Text: Text2.Text = my(26)

For i =1 To Len(mw)

c= Mid(mw, i, 1)
If c>="A" And c<="Z" Or c>="a"
And c<="2"Then
          '（1）_____________
jm =jm+ Mid(Text2.Text, t, 1)
Else
jm=jm +c
End If

Next i

Text3.Text =jm

End Sub
Function my(n As Integer)As String
Dim s As String, i As Integer, x As Integer
s ="ABCDEFGHIKLMNOPQRSTUVWXYZabc-defghijklmnopqrstuvwxyz0123456789"
i=1
Do While i <=n
t=63-i
x =Int(Rnd()*t+1)
         '（2）___________

s = Mid(s, 1, x－1)+ Mid(s, x+1, t－x)

i=i+1

Loop
End Function