以下是引用TonyDeng在2012-3-9 13:15:29的发言：

这代码，楼主估计是难以理解loop的用法，先把程序变换成如下代码，应该好理解了，一样的效果：

 
function cc
    para  cstr
     cresult=space(0)
     for n=1 to len(allt(cstr))
         c=substr(cstr,n,1)
         if between(c,"A","Z") .or. between(c,"a","z")
             cresult=cresult+chr(asc(c)+1)
         endif
     endfor
     return cresult
 endfunc           function cc
    para  cstr
     cresult=space(0)
     for n=1 to len(allt(cstr))
         c=substr(cstr,n,1)
         if ISALPHA(C)
            cresult=cresult+chr(asc(c)+1)
         endif
     endfor
     return cresult
 endfunc