You need to research lenses and adapters for a specific camera. If the lenses are of the type that the digital camera uses, they will work. Otherwise, you need an adapter if one is available. With an adapter, functions such as AF may not work.
I have inherited a bunch of lenses from a family member and want to learn about whether most lenses, older or otherwise, fit on the new digital SLRs. These aren't cheapos, they are pretty good lenses of all kinds.