In context of C++, which of the following is a valid statement ?

Question

Accepted Answer

The correct option is (3):
Keywords private, protected and public may appear in any order and any number of times in a class.
This statement is a correct principle in C++ class design. The access specifiers—`private`, `protected`, and `public`—are used to group class members and define their visibility from outside the class. A programmer is entirely free to organize their class definition by using any of these keywords multiple times and in any sequence they deem necessary for clarity and logical grouping. Each specifier remains active for all subsequent members until the next access specifier is encountered, providing great flexibility in arranging the class's interface and implementation details.

The incorrect option is (1):
Friend function of a class is always member function of that class.
This statement is incorrect by definition. A friend function is explicitly a *non-member* function that has been granted privileged access to the private and protected members of a class. The primary purpose of the `friend` keyword is to allow an external, non-member function to operate intimately with the class's encapsulated data. Because it is not a member, a friend function is called directly by its name, unlike a true member function, which must be invoked using the dot (`.`) or arrow (`->`) operator on a class object.

The incorrect option is (2):
Value of static data member cannot be changed once assigned.
This is false. A static data member is a single, class-level variable shared by all objects of the class, but it is not inherently constant. Like any ordinary, non-constant variable, its value can be modified at any time after its initial definition and assignment outside the class. The rule that a value cannot be changed once assigned only holds true if the static data member is explicitly declared as **`const static`**.

The incorrect option is (4):
Static data member of a class can be accessed only by static member function of that class.
This statement is incorrect regarding access rules. A static data member can be accessed by *both* static and non-static member functions of the class, as it belongs to the class type itself, not a specific object. Furthermore, if the static data member is declared in the `public` section, it can be accessed by *any* non-member function, including the `main` function, by using the class name and the scope resolution operator (`::`).