BATCH- binary with for - windows

Question

I have to make a script that has to calculate the mask and the net, so I'm trying a script with for but it can not convert the IP to binary. I think I'm not using the variables right.
Any ideas?
#echo off
setlocal enabledelayedexpansion
set var=%1
set /p var=Introduce la ip:
for /F "tokens=1 delims=." %%a in ("%var%") do (
echo %%a
set "vara=%%a"
:binario
set bin=2
set /a resto=%vara%%%bin%
set /a a=%vara%/%bin%
set resultado=%resto%%resultado%
if %vara% GTR 0 (goto binario)
echo %resultado%
goto siguiente
)
:siguiente
for /F "tokens=2 delims=." %%b in ("%var%") do (
echo %%b
)
for /F "tokens=3 delims=." %%c in ("%var%") do (
echo %%c
)
for /F "tokens=4 delims=." %%d in ("%var%") do (
echo %%d
)
goto fin
:vacio
echo Error!
goto fin
:fin
pause

Answer 1

You've got a few minor problems that I see. You set var=%1 but you never check to see whether %1 was supplied before doing set /p var=Enter an IP:. You never call or goto :vacio. As I commented above, modulos within batch scripts need to be written as %% to prevent evaluation as variable chararacters. You don't need % in var names in set /a commands, and you can combine multiple set /a statements with a comma. So instead of
set /a resto=%vara%%%bin%
set /a a=%vara%/%bin%
(which is wrong anyway -- I'll get to that in a minute), I suggest this would be more understandable and maintainable:
set /a resto = vara %% bin, numero = vara / bin
The biggest problem is that you appear to be trying to modify %%a. Don't do that.
If I were you, I would move the decimal to binary conversion to a subroutine, and call it for each octet. Try this:
#echo off
setlocal enabledelayedexpansion
set IP=%1
if "%IP%"=="" set /p "IP=Introduce la ip: "
set idx=0
for %%a in (%IP:.= %) do (
if %%a lss 0 goto vacio
if %%a gtr 255 goto vacio
if !idx! gtr 3 goto vacio
set /P "=%%a = "<NUL
call :dec2bin bin[!idx!] %%a
set /a idx += 1
)
echo %bin[0]%.%bin[1]%.%bin[2]%.%bin[3]%
goto fin
:dec2bin <var_para_definir> <numero>
setlocal enabledelayedexpansion
set numero=%~2
set bin=
for /L %%I in (1,1,8) do (
set /a bit = numero %% 2, numero /= 2
set bin=!bit!!bin!
)
echo %bin%
endlocal & set "%~1=%bin%"
goto :EOF
:vacio
echo Error!
goto fin
:fin
pause
For more information about using call as a function that returns a value, see this page.