Latchbolt locks are spring-loaded. The rounded metal end protrudes from the door but because of its shape, it is pushed back into the door as it slides past the door frame and snaps back out into a hole in the frame so it securely holds the door in place. It is then connected to some sort of handle or knob on the inside and a key hole on the outside. When the key turns, it retracts the metal end again and the door can be pushed open. The disadvantage is that when the door slams behind you, it is shut and if a burglar gets into your house, they can easily let themselves back out!
A deadbolt lock is not connected to a door knob or handle. The end of the lock is not spring loaded, it has to be locked into place in the hollow in the door frame. These locks need to be manually locked so it is harder to lock yourself out. Some have a turn-style knob on the inside of the door whilst others have keys. This can be a problem if you need to get out in an emergency.