如果在.bat文件中

Question

@echo off
if "%1"=="" (
:WriteAgain
set x= 
set /p variables=Write your expression 
if "%variables%"=="help" (
echo Use arithmetical operations and numbers without spaces. + for sum, * for multiplication, / for 

devision, - for subtraction 
exit
) else (
set variables=%variables: =%
set /a x=%Variables% 2>Error.txt
if %errorlevel% neq 0 goto ErrorOccured
echo %x% 
pause
exit
)
:ErrorOccured
echo Your expression is not valid 
goto WriteAgain
) else (
set variables=%*
set variables=%variables: =%
set /a x=%variables% 2>Error.txt
if %errorlevel% neq 0 goto ErrorOccured
echo %x%
)

Greetings, It is a simple calc. It could be used right from cmd but first if doesn't work also it can't pass

) else (
set variables=%variables: =%
set /a x=%Variables% 2>Error.txt
if %errorlevel% neq 0 goto ErrorOccured
echo %x%

always ErrorOccured . I don't see any problems and it worked without first if

Answer 1

Perhaps next code could help. Note EnableDelayedExpansion and proper quoting to allow all arithmetic operations seen in set /? .

@ECHO OFF
SETLOCAL EnableExtensions EnableDelayedExpansion
if "%~1"=="" goto NeedHelp
set "variables=%*"

:CommonCalc
if "%variables%"=="" goto ErrorOccured
rem spaces do not matter set "variables=!variables: =!"
set /a "x=!variables!" 2>Error.txt
if %errorlevel% neq 0 goto ErrorOccured
echo !variables!=%x%
exit /B

:WriteAgain
set "x="
set "variables="
set /p "variables=Write your expression: "
if /I "!variables!"=="" goto NeedHelp 
goto CommonCalc

:NeedHelp
echo Use arithmetical operations and numbers without spaces. 
echo + for sum, * for multiplication, / for division, - for subtraction
echo %% for modulus ^(remainder after division^)
goto WriteAgain

:ErrorOccured
echo Your "!variables!" expression is not valid ^(%errorlevel%^)
rem next line: clear errorlevel to 0
(call )
goto NeedHelp

However, proper escaping some operators is needful if used as batch line parameters . For instance:

• negation 32766441.bat ^^^!0 returns !0=1 ,
• logical or 32766441.bat 6^|9 returns 6|9=15 ,
• left shift 32766441.bat 5^<^<3 returns 5<<3=40 etc.

The (call ) trick to clear errorlevel by virtue of this dbenham's answer

Answer 2

I do not know if it fits your expectations and I was not able to run the ErrorOccured label.

@echo off
cls
set x= 

:WriteAgain
if "%1"=="" (
    set /p "variables=Write your expression " || cls &goto help
    ) else (
    set "variables=%*"
)

set variables=%variables: =%
set /a x=%variables% 2>Error.txt
:: if %errorlevel% neq 0 goto ErrorOccured
if not ERRORLEVEL 0 goto ErrorOccured
call :result %variables% %x%
exit /b 0

:help
echo(
echo Use arithmetical operations and numbers without spaces.
echo + for sum, * for multiplication, / for devision, - for subtraction
goto WriteAgain

:result
echo formula is %~1 and the result is %~2
goto:EOF

:ErrorOccured
cls
echo(
echo Your expression is not valid 
goto :help

exit /b 0

This must certainly be optimized.