The Waite Group's C++ Primer Plus, Third Edition

Chapter 9

A1:	A class is a definition of a user-defined type. A class declaration specifies how data is to be stored, and it specifies the methods (class member functions) that can be used to access and manipulate that data.
A2:	A class represents the operations one can perform on a class object with a public interface of class methods; this is abstraction. The class can use private visibility (the default) for data members, meaning that the data can be accessed only through the member functions; this is data hiding. Details of the implementation, such as data representation and method code, is hidden; this is encapsulation.
A3:	The class defines a type, including how it can be used. An object is a variable or other data object, such as that produced ...