lines and i'll draw this line a little bit around p three so it kinda goes like that as all the very adult one interfere with young's convict dr around p_-three what value that start with i don't know it's not pointing to an object exit has a man initialize the point when object has been in this life too point when you object and so if i come along and say here you know what p three i just want to move you work on the five dot right here the parties at four p one mpt_ or can you move yourself or come fuck what happens when i do this bad times that's what happens when i get apart like a social policies that when i get is this thing who knows where it's pointing as a matter fact this pointer could often times be something we refer to as a null which means he's not pointing any particular object in which case when i try to do this i get what's called an old lady reference anyone happen to see something called a null be reference why oregon breakout few folks yet as which are getting you had some object your that wasn't actually pointing anywhere and you are trying to call a method on the test hey i'm trying to call the movement but on p three p three says and i got nothing for you man i've got nothing here and you're trying to move something that doesn't exist so you're trying to d reference which means go through the references the funky name for go through we sadie reference something that doesn't exist or maybe this is just you know have some random valued it's pointing off someone's memory that you don't know about which isn't actually not okay so that's what you want a lot jump or this is a real bad times if you actually happen to call a method on some project which doesn't really exist now the other thing that's important about seeing the little pointers is the fact that remember we talked about parameter passing and in the days of your we talk about grammar passing and he said this little thing where we said hey you know what if you have something like an intern parade double or a car or a boolean these are what we refer to as a primitive types they're like hanging around there you know 