@echo off
rem 已封装
setlocal enabledelayedexpansion
set ctr=0
set "bc=%~1"
set "c=%~2"
set f=false
if "!bc:~0,1!"=="-" if "!c:~0,1!"=="-" (
 set bc=!bc:-=!
 set c=!c:-=!
 set bc=!bc: =!
 set c=!c: =!
 set f=false
) else (
 rem nothing
)
if "!bc:~0,1!"=="-" if "!c:~0,1!" neq "-" (
 set bc=!bc:-=!
 set bc=!bc: =!
 set f=true
) else (
 rem nothing
)
if "!bc:~0,1!" neq "-" if "!c:~0,1!"=="-" (
 set c=!c:-=!
 set c=!c: =!
 set f=true
) else (
 rem nothing
)
set tbc=!bc!
set tc=!c!
set tbc=!tbc:.=!
set tc=!tc:.=!
set tbc=!tbc: =!
set tc=!tc: =!
if !"tbc!" neq "!bc!" if  "!tc!" neq "!c!" (
 for /f "delims=. tokens=1-3 eol=a" %%a in ('echo !bc!') do (
  call :len %%b
  set lenbcx=!zz!
 )
 for /f "delims=. tokens=1-3 eol=a" %%a in ('echo !c!') do (
  call :len %%b
  set lencx=!zz!
 )
) else (
 goto :r
)
if !lenbcx! gtr !lencx! (
 set /a cz=lenbcx-lencx
 for /l %%a in (1,1,!cz!) do (set c=!c!0)
 set c=!c:.=!
 set c=!c: =!
 set bc=!bc:.=!
 set bc=!bc: =!
) else (
 if !lenbcx!==!lencx! set bc=!bc:.=! & set c=!c:.=! & set bc=!bc: =! & set c=!c: =! & goto :r
 set /a cz=lencx-lenbcx
 for /l %%a in (1,1,!cz!) do (set bc=!bc!0)
 set c=!c:.=!
 set c=!c: =!
 set bc=!bc:.=!
 set bc=!bc: =!
)
:r
for /l %%a in (1,1,9) do (if "!bc:~0,1!"=="0" set bc=!bc:~1!)
for /l %%a in (1,1,9) do (if "!c:~0,1!"=="0" set c=!c:~1!)
set /a "s=bc/c"
set /a "m=bc %% c"
if !m!==0 goto :f
set s=!s!.
:main
if !m!==0 goto :f
for /l %%a in (1,1,8) do (
 if !m! lss !c! (
  set /a m=m*10
  if %%a geq 2 set s=!s!0 & set /a ctr+=1
 ) else (
 rem nothing
 )
)
set /a "ss=m/c"
set /a "m=m %% !c!"
set s=!s!!ss!
set s=!s: =!
set /a ctr+=1
if !ctr! gtr 10 goto :f
goto :main
:f
if !f!==false (
 echo !s!
) else (
 echo -!s!
)
goto :eof
:len
set "t=%1"
set zz=0
for /l %%a in (0,1,11) do (
 if "!t:~%%a,1!"=="" goto :eof
 set /a zz+=1
)
goto:eof
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@echo off&setlocal enabledelayedexpansion
title 批处理小数运算。
set /p input=输入算式(如 2.96+0.907) ：
for /f "tokens=1,2 delims=+-*/" %%a in ("%input%") do (
	set x=%%a & set y=%%b
	call set symbol=%%input:%%a=%%
	call set symbol=%%symbol:%%b=%%
)
set /p precision=自定义精度(默认为3)：
if not defined precision set precision=3
set /a xsd=1
for /l %%a in (1 1 %precision%) do set /a xsd*=10
echo;
rem echo;思路：先将数字放大%xsd%倍，得到结果再缩小%xsd%倍。
set/p=%x%  %symbol% %y% 的值为:<nul 
call :largen x %precision%
call :largen y %precision%
if "%symbol%"=="*" set expression=x*y & set /a z=!expression!/%xsd%
if "%symbol%"=="/" set expression=x/y & set /a z=!expression!*%xsd%
if "%symbol%"=="+" set expression=x+y & set /a z=!expression!
if "%symbol%"=="-" set expression=x-y & set /a z=!expression!
call :output z 
echo;
pause&exit /b

:largen              
setlocal
set bignum=!%~1!
set /a _precision=%~2 + 1
for /l %%n in (1,1,%_precision%) do set zero=!zero!0
set multiple=1%zero%
for /f "tokens=1,2 delims=. " %%a in ("%bignum%") do (
	set bignum_b=%%a&set bignum_e=%%b%zero%
)
set bignum_e=1!bignum_e:~0,%_precision%!
set /a smallnum=bignum_b*multiple+bignum_e
set /a smallnum+=5
set /a smallnum-=multiple
set smallnum=%smallnum:~0,-1%
endlocal & set %~1=%smallnum%
goto :eof
  
:lessen 
setlocal
set smallnum=!%~1!
set _precision=%~2
for /l %%n in (1,1,%_precision%) do set zero=!zero!0
set multiple=1%zero%
set /a bignum_b=smallnum/multiple
set /a bignum_e=smallnum%%multiple
set bignum_e=%zero%%bignum_e%
set bignum_e=!bignum_e:~-%_precision%!
set bignum=%bignum_b%.%bignum_e%
endlocal & set %~1=%bignum%
goto :eof

:output
call :lessen %~1 %precision%
set/p=	!z!<nul
goto :eof
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set/p "input=输入表达示：
for /f "delims=" %%a in ('powershell "%input%"') do echo %%a
pause
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