Demon

既然rand是伪随机数，%random%当然也是伪随机数。

@echo off
setlocal enabledelayedexpansion
set /a x = !random!
echo !x!
echo;
call :time t
for /l %%i in (%t%, -1, 0) do (
    set /a y = ((%%i * 214013 + 2531011^) ^>^> 16^) ^& 0x7fff
    if !y! equ !x! (
        echo %%i
        call :srand %%i
        call :rand z
        echo !z!
        echo;
        for /l %%j in (1, 1, 10) do (
            call :rand z
            echo !z! !random!
        )
    )
    echo;
    pause & exit
)

:time
setlocal
for /f %%x in ('wmic path win32_utctime get /format:list ^| findstr .') do set %%x
set /a year = year - 1900, t = (year - 70) * 365 + ((year - 1) ^>^> 2) - 17, leap = year ^& 3
for /f "tokens=%month%" %%i in ("-1 30 58 89 119 150 180 211 242 272 303 333 364") do set /a t += %%i
if %leap% equ 0 if %month% gtr 1 set /a t += 1
set /a t += day, t *= 24, t += hour, t *= 60, t += minute, t *= 60, t += second
endlocal & set %1=%t%
goto :eof

:srand
set /a _holdrand = %1
goto :eof

:rand
set /a _holdrand = _holdrand * 214013 + 2531011
set /a %1 = (_holdrand ^>^> 16) ^& 0x7fff
goto :eof
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Demon

回复  Demon


    核心的那两行如何得到的， 214013 ，2531011这两个常数？
-------------------
友 ...
plp626 发表于 2012-8-30 23:26

请指点。

Demon

回复  Demon


    日期算法：
CrLf 发表于 2012-8-31 11:33

@echo off
call :time t
echo %t%
pause & exit

:time
setlocal
for /f "skip=1 tokens=1-9" %%a in ('wmic path win32_utctime ^| findstr .') do set /a m=%%e+9,m%%=12,y=%%i-m/10,t=365*y+y/4-y/100+y/400+(m*306+5)/10+%%a-719469,t=t*86400+%%c*3600+%%d*60+%%g
endlocal & set %1=%t% & goto :eof
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这种Write Only的代码是反人类的。