a funny piece of code on the lab door

when the 2nd week i came to augsburg, i found that there is a piece of c++ code on the door of experimental physik II, quite interesting, there are geeks here. ^_^ 7h3r3 4r3 633k5 h3r3.

#include "doors"
if (door_is_closed()){
try{
open_door();
}catch(door_locked){
goto next_door;
}
}
next_door:
try{
open_next_door(/* \longleftarrow */);
}catch(door_locked){
goto home;
}
home:
go_home() XOR try_again_later();