Compound sentences

[Roey]

The boy came in and sat down.
The boy came in and he sat down.

Are both of these sentences considered "compound" (2 clauses of equal weight joined by a conjunction/ connective?) Or only the second, since it specifically repeats the subject whereas in the first, the subject is "understood"?

[susiedqq]

The clue in a compound sentence would be if each thought could stand alone.

He came in the door and Mary stood up.

[Roey]

Thanks Susie-I'm still unsure though!

In your example, would BOTH these two versions be compound sentences i.e.

He came in the door and he stood up.
He came in the door and stood up.


or only the FIRST one since "and stood up" in the second one, doesn't stand on it's own (despite the fact that the subjectof this clause is the same as the first, simply not restated?)