凱薩密碼系統

Private Sub Command1_Click()
'第一題，加密後放text2
    Text2 = ""
    For i = 1 To Len(Text1)
        Text2 = Text2 & Chr(Asc(Mid(Text1, i, 1)) + Text4)
    Next
End Sub

Private Sub Command2_Click()
'第二題，解密後放text3
    Text3 = ""
    For i = 1 To Len(Text2)
        Text3 = Text3 & Chr(Asc(Mid(Text2, i, 1)) - Text4)
    Next
End Sub

Private Sub Command3_Click()
'第三題，解密後放text6
    n = -10
    Text6 = ""
    For i = 1 To Len(Text5)
        Text6 = Text6 & Chr(Asc(Mid(Text5, i, 1)) + n)
    Next
End Sub

Private Sub Command4_Click()
'第四題，轉盤解碼
    Timer1.Interval = 800
    Label2 = 26
End Sub

Private Sub Timer1_Timer()
    Me.Cls  '清除form1上面的所有作畫

    'cos(n)，n的值由0-2PI
    '***********下面的cos(0) sin(0)請參考講義改寫她才會轉動*************
    x = (Image1.Left + Image1.Width / 2) + 2800 * Cos(Label2 * 2 / 53 * 3.14)
    y = (Image1.Top + Image1.Height / 2) + 2800 * Sin(Label2 * 2 / 53 * 3.14)
    '*******************************************************************

    '畫線，從中心點到上述算出的角度座標
    Line ((Image1.Left + Image1.Width / 2), (Image1.Top + Image1.Height / 2))-(x, y), vbRed

    '*********第四題，解碼並用instr檢查是否正確
    Text6 = ""
    For i = 1 To Len(Text5)
    Text6 = Text6 & Chr(Asc(Mid(Text5, i, 1)) - Label2)
    Next
    If InStr(Text6, Text7) Then
    MsgBox Label2
    Timer1.Interval = 0
    Else
    Label2 = Label2 - 1
    End If

End Sub