大小写转换(ROBOT)

declare function size(aa as string) as string 
sub main
dim a,as_string as string
a=inputbox("please input first number")
as_string=size(a)
end sub

function size(a as string)
 
  dim a_a,size_na,size_length,A_string,size_test as string
  dim q,w,a_if,a_instr ,a_length as integer
  size_length=""
  a_length=len(a)
'根据长度折分
for q=1 to a_length

   a_a=mid(a,q,1)
  
   a_if=instr("abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ",a_a)
   A_string="ABCDEFGHIJKLMNOPQRSTUVWXYZ"
  
   if(a_if>26) then
     size_na=a_a
   else
     size_na=mid(A_string,a_if,1)
    'msgbox size_na+"***"
   end if
    size_length=size_length+size_na
 next q

msgbox size_length

   'msgbox a_if
    'if(a_if>26 or a_if<1) then
    'a =inputbox("请重新输入")
   ' end if
 
 
   ' msgbox size_na
   
   'size_na=lof(a)

 'msgbox size_na

end function