Add.bat

@SET %ERRORLEVEL%=0
REM Error checks
@IF "%~1"=="" (ECHO ERROR: No Input^! Try "Add help"&&PAUSE&&EXIT /b 1)

@IF /I "%~1"=="help" goto help
@IF "%~1"=="?" goto help

@SET /a errorcheck=%~1 >nul 2>&1
@IF NOT %ERRORLEVEL% EQU 0 (ECHO Add only accepts integer number input^! Try "Add Help"&&PAUSE&&EXIT /b 1)
@IF "%~2"=="" (ECHO ERROR: Missing second input^! try "Add help"&&PAUSE&&EXIT /b 1)
@SET /a errorcheck=%~2 >nul 2>&1
@IF NOT %ERRORLEVEL% EQU 0 (ECHO Add only accepts integer number input^! Try "Add Help"&&PAUSE&&EXIT /b 1)

REM Actual maths
@SET /a "result=%1+%2"
@ECHO %1 + %2 = %result%
exit /b 0

REM Help message
:help
ECHO Addition of two integer numbers
ECHO.
ECHO Example usage:
ECHO Add [Number] [Number]
ECHO Result is stored in ^%result^%
ECHO.
ECHO Add [?/help]
ECHO Display this help message.
ECHO.
PAUSE
EXIT /b 0