If you are in US, most hospitals can give you a tour of the facility. They'll also answer all your questions and preregister you right then.
I strongly encourage you to do that.
You dont need diapers for the hospital the hospital will provide you with them for the days youre there(: & you will use the newborn ones for not thst long cus babies usually start using size onw real quick so try not to get to many newborn ones well thats my opinion as im expecting baby #4(:
Most hospitals provide diapers and wipes for you as well as formula if you are not breast feeding. If you want to just be sure I would bring a small pack just in case they don't provide them at your hospital.
The hospital never provided diapers for me... you had to bring your own... and I found premature diapers woked great for the first couple weeks even though my baby was full term. They just fit better. I brought a bunch. Only ended up needing like 7 or 8 though lol