vb:编写程序，统计文本框输入的一段英文段落中，字母"a","b","c"出现的次数和频率

Private Sub Command1_Click()
Dim S as string,A(1 to 3) as integer
S=Ucase(text1.text)
For i=1 to Len(S)
c=(Mid(S,i,1)
If C>="A" And C<="C" Then
A(Asc(C)-64)=A(Asc(C)-64)+1
End If
Next
For i=1 to 3
Print Chr(64+i) & "出现:" & A(i) & "次,出现频率:" & A(i)*100/Len(S) & "%"
Next
End Sub

private sub Command1_Click()

a=UBound(Split(text1.text, "a")
b=UBound(Split(text1.text, "b")
c=UBound(Split(text1.text, "c")
print "a出现 " & a & "次,b出现 " & b & "次,c出现 " & c & "次!"

end sub

自己加一下循环吧
Public Function ABC(string1 As String, string2 As String) As Integer
Dim jsq
On Error GoTo err
i = 1
Do
If (i > Len(string1)) Then Exit Do
i = InStr(i, string1, string2)
If i <> 0 Then
jsq = jsq + 1
End If
i = i +