- "Object-oriented programming is programming using inheritance. Data abstraction is programming using user-defined types. With few exceptions, object-oriented programming can and ought to be a superset of data abstraction."
P.s. Ravi Sethi says in his Programming Languages: "The popular term object-oriented programming refers to a programming style that relies on the concepts of inheritance and data encapsulation." (p.206, 1989). I seem to have been right on the money (or perhaps I just retrieved this info, subconsciously, from my memory?)