VB程序,输入一串字符,统计其中的各个英文字符的个数(不分大小写)?

Private Sub Form_Click()
Dim char As String * 1, n%
Dim letter(1 To 26) As Integer
For i = 1 To Len(Text1)
char = LCase(Mid(Text1, i, 1))
If char >= "a" And char <= "z" Then
n = Asc(char) - Asc("a") + 1
letter(n) = letter(n) + 1
End If
Next i
For i = 1 To 26
If letter(i) <> 0 Then
Text1 = Text1 & "含有" & Chr(Asc("a") + i - 1) & "字母" & letter(i) & "个; "
End If
Next i
End Sub
'这是我写的代码,不明白的地方提出来哟!~ ^_^b