<P> A class in C++ is a user defined type or data structure declared with keyword class that has data and functions (also called methods) as its members whose access is governed by the three access specifiers private, protected or public (by default access to members of a class is private). The private members are not accessible outside the class; they can be accessed only through methods of the class . The public members form an interface to the class and are accessible outside the class . </P> <P> Instances of a class data type are known as objects and can contain member variables, constants, member functions, and overloaded operators defined by the programmer . </P> <P> In C++, a class defined with the class keyword has private members and base classes by default . A structure is a class defined with the struct keyword . Its members and base classes are public by default . </P>

Why class is called as reference data type
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