Agreed, but it doesn't explain the design technique.
ISTM that it provides encapsulation. But AIUI encapsulation, isn't of itself, OO.
Just like the other poster, I don't know anywhere near enough about OO to understand exactly how it works and what part of a language supports it, or is necessary to provide it.
I understand some things, like the exported interface that Chuck was on about and how it can be used. For example, one can make several IO devices all look the same, so that an application can supply one code line for "output" and it will work whatever device it is currectly selected to output to. (Very useful now that portable devices have so many ways of communicating with the outside world)
OTOH, I am currently working with (someone elses) C++ implementation which hides associated things in classes, but many of which are accessed from other classes using lots of structure and :: (whatever that's called) operators.
Some of these accesses are **** complicated to get to compile and to me, don't seem to provide useful encapsulation at all. They just look like access to global variables using an unnecesary complicated syntax. The 15 people who penned this code in the first place are supposed to know what they are doing, and I am not. I'm not convinced.
tim