Pow Function

::---------------------------------------------------------------------------------------
::  square a number
::
:: call :pow 12 2 RETURNVAR
:: echo %RETURNVAR%
::---------------------------------------------------------------------------------------
:pow
    setlocal
        set "out=1"
        for /l %%a in (1,1,%2) do set /a "out*=%1"
        if %~1 equ 0 set "out=1"

        (endlocal
            if "%~3" neq "" ( set "%~3=%out%" ) else echo %out%
        )
goto :eof
::---------------------------------------------------------------------------------------