①从左往右依次获取各字符的ASCII码值;
②对奇数位字符的ASCII码值做加法处理,对偶数位字符的ASCII码值做减法处理;
③将上述结果取绝对值后除以26求余数,余数为0~25,分别对应大写字母A~Z,则该大写字母即为验证字符。
小李编写字符串验证程序,功能如下:在文本框Text1中输入待检验字符串(最后一位为验证字符),点击按钮Command1,在标签Label1中显示输入字符串是否验证成功。程序运行界面如图所示。
Private Sub Command1_Click()
Dim s As String, t As String
Dim cha As Integer, ans As Integer
Dim a As Integer, b As Integer, i As Integer
s =
t = Mid(s, Len(s), 1)
ans = 0
For i = 1 To Len(s) - 1
cha = Asc(Mid(s, i, 1))
If Then
ans = ans - cha
Else
ans = ans + cha
End If
Next i
ans = Abs(ans) Mod 26
If Then
Label1.Caption = "验证成功!"
Else
Label1.Caption = "验证失败!"
End If
End Sub