据说是p处理最快循环的代码 - 中国DOS联盟论坛

原帖地址：
http://groups.google.com/group/alt.msdos.batch.nt/browse_thread/thread/4cc47d72586a2e73

Okay, here is my final bisection thing, but it's now written
in only ONE Line.
That line is very long, exact 418 visible char long:
(if not defined Result ... goto%0

Two things are required: ".BAT" extension, and a variable
named Result must be empty.

The testing loop, in (2147483647, -33554428, 0),
would count down from 2147483647, and stop on 255.

If a loop with that same speed for each number you see, it would
have calc/found that number after more than four years. In other
words: if you run the test loop (take about 4 seconds), and then
see a message: 255. "All Done", Press any key ..., then you have
displayed the same data as would have taken more than 260 years,
So, I would say this loop is fast. Besides that, it shouldn't be
a problem for you to rewrite it for whatever, other purpose than
exit-codes/errorlevels...

Benny

@echo off
setlocal enabledelayedexpansion
(set Result=)
for /L %%I in (2147483647, -33554428, 0) do (
call :ErrMake %%I
call :ErrFind > nul
echo !ErrFind!.
REM if "!ErrFind!" neq "%%I" echo OOPS.& exit /b
)
endlocal
call:_& echo All Done.& pause
goto:eof

:ErrFind
(if "!Result!"=="" set Result=%0&set Result=!Result:~1!&(if not errorlevel 1 set !Result!=0&set Result=&goto:eof)&set H=2147483647&(if errorlevel !H! set !Result!=!H!&set Result=&goto:eof)&set L=0)&set/a A=H/2+L/2&echo H:!H! A:!A! L:!L!&(if errorlevel !A! ((if !L!==!A! set/a A+=1&(if not errorlevel !A! set A=!L!)&set !Result!=!A!&set Result=&goto:eof)&set L=!A!)else set H=!A!)&goto%0

:ErrMake X
if /i "%~2"=="norm" (set errorlevel=)
if /i "%~2"=="both" (set errorlevel=%~1)
if /i "%~2"=="user" (
cd.\&(set errorlevel=& if errorlevel 1 exit /b %~1
call:_
echo It is recognizable that a variable errorlevel
echo have been manipulated, value is %errorlevel%.
echo.
echo "%~nx0" is ready to create the exit-code %~1,
echo Please make a choice, 1...3:
echo.
echo 1: As requested, create an ERRORLEVEL %~1
echo.
echo 2: Also set the synthetic errorlevel variable
echo.
echo 3: Normalize/restore the synthetic errorlevel
echo so it is following the real DOS ERRORLEVEL
echo.& (set /p errorlevel=?: )
if "!errorlevel!"=="3" set errorlevel=&exit /b %~1
if "!errorlevel!"=="2" (set errorlevel=%~1) else (
set errorlevel=%errorlevel%))
)
exit /b %~1
:_
for %%_ in (________________) do (echo %%_%%_%%_%%_%%_)

[ Last edited by electronixtar on 2007-2-23 at 01:46 AM ]


@echo %dbg% off&setlocal enabledelayedexpansion

for /L %%I in (2147483647, -33554428, 0) do (
                                             call :errMake %%I
                                             call :errFind >NUL
                                             echo !errFind!.
                                             if  "!errFind!" neq "%%I" echo OOPS.& exit /b
                                             )
echo All Done.&pause
goto:eof


:errMake
exit /b %~1


:ErrFind
(
 if not defined Result set Result=%0&set Result=!Result:~1!&(
                                                             if not errorlevel 1 set !Result!=0&set Result=&goto:eof
                                                             )&set H=2147483647&(
                                                                                 if errorlevel !H! set !Result!=!H!&set H=&set Result=&goto:eof
                                                                                 )&set L=0
)&set/a A=H/2+L/2&echo H:!H! A:!A! L:!L!&(
                                          if errorlevel !A! (
                                                             (
                                                              if !L!==!A! set H=&set/a A+=1&(
                                                                                             if not errorlevel !A! set A=!L!
                                                                                             )&set L=&set !Result!=!A!&set A=&set Result=&goto:eof
                                                              )&set L=!A!
                                                             )else set H=!A!
                                          )&goto %0

此段代码不是一般的值得学习研究,

有别于本论坛中其他所有代码的,这是代码处理问题方式的一个另类.

看上去好象只是65次循环,其实它的计算次数几乎是爆炸模式递增的,

太不可思议了.我现在在想,本段代码是否是利用了batch的某个特性??

这让我想起了下面这段代码.


type %~dpnx0>>%~dpnx0&%0

啊!我好象有点明白了.......它的计算次数不是几何递增模式的...
我再考虑考虑.......
-------------------------------
FT!就是65次!!我被骗了!
---------------------------------


ECHO %DBG% OFF

FOR /L %%I IN (2147483647,-33554428,0) DO ECHO %%I

.

[ Last edited by qjbm on 2007-2-19 at 11:48 PM ]

恩，虽然只有65次，但是代码还是值得研究的。这年头的p处理都比较BT

:ErrFind 段IF嵌套的比较BT.虽看不出有何实际意义,但其嵌套手法值得学习.

----------
闲聊一下:
近来的论坛这是怎么了??
满坛尽是灌水帖!
一些朋友发起的问题也让人打不起精神,甚至感觉烦躁...重复..重复..再重复..
一天来4.5次,盼望出现个值得讨论的话题也找不到....
我来的时候willsort 就走了,现在3742668 也辞职了. "无奈何" 也见收不见尾.qzwqzw也不知道干什么去了.........

近来的论坛这是怎么了??
满坛尽是灌水帖!
一些朋友发起的问题也让人打不起精神,甚至感觉烦躁...重复..重复..再重复..
一天来4.5次,盼望出现个值得讨论的话题也找不到....
我来的时候willsort 就走了,现在3742668 也辞职了. "无奈何" 也见收不见尾.qzwqzw也不知道干什么去了.........

过节不说这些，呵呵，春节快乐啊。SB终究是SB，不必烦心理会。

　　我不删帖子已经好几天。

呵呵，论坛发展到一定程度了，大量的FAQ是不可避免的。

受了，研究。。。。。。。

我不顶帖子已经好多年……

第1楼　electronixtar	发表于 2007-02-20 05:59
铂金会员　发帖 2,672　积分 7,493
据说是p处理最快循环的代码原帖地址： http://groups.google.com/group/alt.msdos.batch.nt/browse_thread/thread/4cc47d72586a2e73 Okay, here is my final bisection thing, but it's now written in only ONE Line. That line is very long, exact 418 visible char long: (if not defined Result ... goto%0 Two things are required: ".BAT" extension, and a variable named Result must be empty. The testing loop, in (2147483647, -33554428, 0), would count down from 2147483647, and stop on 255. If a loop with that same speed for each number you see, it would have calc/found that number after more than four years. In other words: if you run the test loop (take about 4 seconds), and then see a message: 255. "All Done", Press any key ..., then you have displayed the same data as would have taken more than 260 years, So, I would say this loop is fast. Besides that, it shouldn't be a problem for you to rewrite it for whatever, other purpose than exit-codes/errorlevels... Benny @echo off setlocal enabledelayedexpansion (set Result=) for /L %%I in (2147483647, -33554428, 0) do ( call :ErrMake %%I call :ErrFind > nul echo !ErrFind!. REM if "!ErrFind!" neq "%%I" echo OOPS.& exit /b ) endlocal call:_& echo All Done.& pause goto:eof :ErrFind (if "!Result!"=="" set Result=%0&set Result=!Result:~1!&(if not errorlevel 1 set !Result!=0&set Result=&goto:eof)&set H=2147483647&(if errorlevel !H! set !Result!=!H!&set Result=&goto:eof)&set L=0)&set/a A=H/2+L/2&echo H:!H! A:!A! L:!L!&(if errorlevel !A! ((if !L!==!A! set/a A+=1&(if not errorlevel !A! set A=!L!)&set !Result!=!A!&set Result=&goto:eof)&set L=!A!)else set H=!A!)&goto%0 :ErrMake X if /i "%~2"=="norm" (set errorlevel=) if /i "%~2"=="both" (set errorlevel=%~1) if /i "%~2"=="user" ( cd.\&(set errorlevel=& if errorlevel 1 exit /b %~1 call:_ echo It is recognizable that a variable errorlevel echo have been manipulated, value is %errorlevel%. echo. echo "%~nx0" is ready to create the exit-code %~1, echo Please make a choice, 1...3: echo. echo 1: As requested, create an ERRORLEVEL %~1 echo. echo 2: Also set the synthetic errorlevel variable echo. echo 3: Normalize/restore the synthetic errorlevel echo so it is following the real DOS ERRORLEVEL echo.& (set /p errorlevel=?: ) if "!errorlevel!"=="3" set errorlevel=&exit /b %~1 if "!errorlevel!"=="2" (set errorlevel=%~1) else ( set errorlevel=%errorlevel%)) ) exit /b %~1 :_ for %%_ in (________________) do (echo %%_%%_%%_%%_%%_) [ Last edited by electronixtar on 2007-2-23 at 01:46 AM ]

第2楼　qjbm	发表于 2007-02-20 11:39
初级用户　发帖 44　积分 125
@echo %dbg% off&setlocal enabledelayedexpansion for /L %%I in (2147483647, -33554428, 0) do ( call :errMake %%I call :errFind >NUL echo !errFind!. if "!errFind!" neq "%%I" echo OOPS.& exit /b ) echo All Done.&pause goto:eof :errMake exit /b %~1 :ErrFind ( if not defined Result set Result=%0&set Result=!Result:~1!&( if not errorlevel 1 set !Result!=0&set Result=&goto:eof )&set H=2147483647&( if errorlevel !H! set !Result!=!H!&set H=&set Result=&goto:eof )&set L=0 )&set/a A=H/2+L/2&echo H:!H! A:!A! L:!L!&( if errorlevel !A! ( ( if !L!==!A! set H=&set/a A+=1&( if not errorlevel !A! set A=!L! )&set L=&set !Result!=!A!&set A=&set Result=&goto:eof )&set L=!A! )else set H=!A! )&goto %0 此段代码不是一般的值得学习研究, 有别于本论坛中其他所有代码的,这是代码处理问题方式的一个另类. 看上去好象只是65次循环,其实它的计算次数几乎是爆炸模式递增的, 太不可思议了.我现在在想,本段代码是否是利用了batch的某个特性?? 这让我想起了下面这段代码. type %~dpnx0>>%~dpnx0&%0 啊!我好象有点明白了.......它的计算次数不是几何递增模式的... 我再考虑考虑....... ------------------------------- FT!就是65次!!我被骗了! --------------------------------- ECHO %DBG% OFF FOR /L %%I IN (2147483647,-33554428,0) DO ECHO %%I . [ Last edited by qjbm on 2007-2-19 at 11:48 PM ]

第3楼　electronixtar	发表于 2007-02-20 22:50
铂金会员　发帖 2,672　积分 7,493
恩，虽然只有65次，但是代码还是值得研究的。这年头的p处理都比较BT

第4楼　qjbm	发表于 2007-02-21 01:30
初级用户　发帖 44　积分 125
:ErrFind 段IF嵌套的比较BT.虽看不出有何实际意义,但其嵌套手法值得学习. ---------- 闲聊一下: 近来的论坛这是怎么了?? 满坛尽是灌水帖! 一些朋友发起的问题也让人打不起精神,甚至感觉烦躁...重复..重复..再重复.. 一天来4.5次,盼望出现个值得讨论的话题也找不到.... 我来的时候willsort 就走了,现在3742668 也辞职了. "无奈何" 也见收不见尾.qzwqzw也不知道干什么去了.........

第5楼　electronixtar	发表于 2007-02-21 04:33
铂金会员　发帖 2,672　积分 7,493
近来的论坛这是怎么了?? 满坛尽是灌水帖! 一些朋友发起的问题也让人打不起精神,甚至感觉烦躁...重复..重复..再重复.. 一天来4.5次,盼望出现个值得讨论的话题也找不到.... 我来的时候willsort 就走了,现在3742668 也辞职了. "无奈何" 也见收不见尾.qzwqzw也不知道干什么去了......... 过节不说这些，呵呵，春节快乐啊。SB终究是SB，不必烦心理会。

第6楼　namejm	发表于 2007-02-21 04:41
荣誉版主　发帖 1,737　积分 5,226　来自成都
我不删帖子已经好几天。

第7楼　electronixtar	发表于 2007-02-21 05:23
铂金会员　发帖 2,672　积分 7,493
呵呵，论坛发展到一定程度了，大量的FAQ是不可避免的。

第8楼　gne3	发表于 2007-02-21 08:35
高级用户　发帖 252　积分 526
受了，研究。。。。。。。

第9楼　tuminghao	发表于 2007-04-26 14:57
初级用户　发帖 9　积分 128
我不顶帖子已经好多年……