中国DOS联盟

@echo off&setlocal enabledelayedexpansion
set "str=ab"&set /a a=%random%%%60+1
:begin
set /a b=%random%%%2
set c=!str:~%b%,1!&set var=%var%!c!
set /a n+=1
if %n% lss %a% goto begin
echo 下面为本次生成的字符串：
echo %var%
set "str="&set n=0
:lp
if !n! lss 60 if defined var (
   set /a b=%random%%%2
   if !b! equ 0 (
      set "b= "
      ) else (
      set b=!var:~,1!&set /a n+=1
   )
   set str=%str%!b!
   set var=%var:~1%
   goto lp
)
echo.%str%
if !n! lss 60 set var=%str%&set str=&goto lp
pause>nul