basic java question

Hey, I realize this isn't linux related, but all the java communities I can find are for advanced users and not only am I not one of those, but this is a basic question.

I can't think of a single reason to use int to assign for numbers rather than the floating decimal available in double. I asked for a good reason n class tonight and I got nothing apart from "You should definately use int, all right".

I suspect there IS a reason or it wouldn't be there. And I see that there's a difference, I just can't think of a reason I would ever need to use 45 when 45.0 will do just as well.

Anyone got anyhting?