题目

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 ① ②  答案：【1】t= Asc(c) Mod 32【2】my=i my+ Mid(s,x,1)

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