@echo off&setlocal
:c
set x1=100
set x2=200
set/ai+=1
if %i% leq 4 echo x1:%x1% x2:%x2%&call:c%i% x1 x2&call echo x1:%%x1%% x2:%%x2%%&echo.&goto:c
pause
exit/b

:c1
call set a=%%%1%%&call set b=%%%2%%
set a=%b%&set b=%a%
set %1=%a%&set %2=%b%
goto:eof

:c2
set/a%1+=%2,%2=%1-%2,%1-=%2
goto:eof

:c3
set/a%1^^=%2,%2^^=%1,%1^^=%2
goto:eof

:c4
set/at=%1,%1=%2,%2=t
goto:eof