title: How to manipulate CString's content
body: <p>guys, I have a problem, please help me!
  I have a CString variable which will receieve from Database,and the data may like this:(8)(9)(10)(11) or more.
  <p>Now I want to change every number in CString,for example, add 1,the outcome should like this:
  <p> CString Data; the contest of CString data variable should be changed.
  <p> Before: (8)(9)(10)(11)
  <p> After:  (9)(10)(11)(12) </p>
  
  <p><p> I've tried Data.GetAt(i),but it returns a const pointer and I can't change it.
  <p> I konw maybe Data.GetBuffer() can get a pointer to manipulate CString,but I don't know how to do it.</p>
  
  <p><p>So please help me ! Thanks a lot!</p>