用vb编程:用输入函数对话框输入字母,然后对其分类,分为大小写

sub test()
Dim S As String
Dim C As String
Dim Sl, Su, Sn As String
Dim L As Integer
Dim I As Integer
Dim V As Integer
S = InputBox("请输入一组字符串", "输入")
L = Len(S)
Sl = "": Su = "": Sn = ""
For I = 1 To L
C = Mid(S, I, 1)
V = Asc(C)
If V >= 48 And V <= 57 Then Sn = Sn & C
If V >= 65 And V <= 90 Then Su = Su & C
If V >= 97 And V <= 122 Then Sl = Sl & C
Next I
MsgBox "数字：" & Sn & Chr(13) & "小写：" & Su & Chr(13) & "大写：" & Sl
end sub

利用ASCII码
大于 97是小a 小于97的是大写的 大小写之间相差 97-65个数值
代码如下：
dim da
dim xiao
a=inputbox("输入字母","输入：","AvAbcdSDSaaBVVV")
lna=len(a)
for i=1 to lna
tem=mid(a,i,1)
if Asc(tem)>=97 then
xiao=xiao & tem
else
da=da & tem
end if
next
msgbox "大写字母有:"