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Right CHOICE is (d) Functions using only STATIC data and can be accessed directly in main() function

Explanation: The static MEMBER functions can be accessed directly in the main function. There is no restriction on direct use. We can call them with use of objects also. But the restriction is that the static member functions can only use the static data MEMBERS of the CLASS.

Right option is (a) Ones defined simply without any type

Best explanation: When there is no type defined for any FUNCTION and just a SIMPLE syntax is USED with the return type, function name and parameter LIST then those are known as simple member functions. This is a general DEFINITION of simple members.

Correct choice is (d) 5

The best EXPLANATION: There are basically 5 types of member functions possible. The types include simple, static, const, inline, and FRIEND member functions. Any of these types can be used in a program as per requirements.

Right answer is (d) Private, public, or protected

Best explanation: The DERIVED class implements the definition of the abstract METHODS of BASE class. Those can be MADE private in derived class if security is NEEDED. There won’t be any problem in declaring it as private.

The CORRECT OPTION is (a) Private

The explanation is: The base class must not contain the abstract methods. The methods have to be derived and defined in derived class. But if it is MADE private it can’t be inherited. HENCE we can’t declare it as a private member.

Right OPTION is (b) It MUST have same prototype in both base and derived class

The EXPLANATION is: The prototype must be the same. This is to override the function declared as abstract in base class. Or ELSE it will not be possible to override the abstract function of base class and hence we GET a compile time error.

The correct option is (c) Abstract METHODS must not be static

Explanation: The abstract methods can never be made static. Even if it is in DERIVED class, it can’t be made static. If this happens, then all the subsequent SUB classes will have a common definition of abstract FUNCTION which is not desirable.

Correct option is (a) True

Explanation: The abstract functions can’t be made static in a PROGRAM. If those are made static then the function will be a PROPERTY of class RATHER than each object. In TURN ever object or derived class must use the common definition given in the base class. But abstract functions can’t be defined in the base class. Hence not possible.

The correct choice is (b) Derived CLASS should be made abstract class

To explain: If the FUNCTION that is not to be defined in derived class but is declared as abstract in BASE class then the derived class must be made an abstract class. This will make the concept MANDATORY that the derived class must have one SUBCLASS to define that method.

Right ANSWER is (a) abstractmethod_name (parameter)

The BEST explanation: The syntax must firstly contain the access modifier. Then the keyword abstract is written to mention clearly to the compiler that it is an abstract METHOD. Then PROTOTYPE of the function with return type, function NAME and parameters.

Correct option is (B) Compile time

The best I can explain: When the program is compiled, these definitions are checked if properly defined. This COMPILER also ensure that the FUNCTION is being defined by all the derived classes. HENCE we get a compile time error if not DONE.

The correct option is (c) Necessary for all the derived classes

For EXPLANATION: The derived classes MUST DEFINE the abstract function of BASE class in their own body. This is a necessary CONDITION. Because the abstract functions doesn’t contain any definition in base class and hence becomes mandatory for the derived class to define them. All the functions in a program must have some definition.

The correct OPTION is (d) ABSTRACT functions must be defined in all the DERIVED classes

For explanation: The abstract function are only declared in BASE classes and then has to be defined in all the derived classes. This allows all the derived classes to define own definition of any function whose declaration in base CLASS might be common to all the other derived classes.

Correct choice is (a) A CLASS may have virtual destructor but not virtual constructor

The explanation: Any class can CONTAIN virtual destructor. But is not possible to define a virtual constructor. The REASON behind is that the DESTRUCTORS can be overridden but CONSTRUCTORS should not be.

Correct answer is (b) Not necessary

For explanation: It is not necessary to redefine the virtual FUNCTION in the derived class. If not defined, the base class function definition is USED but if defined, the intended definition is used ACCORDING to need. It is not about good coding PRACTICE as it should be REDEFINED only if needed.

Correct choice is (d) Base, derived

The best I can explain: The virtual FUNCTIONS must be declared and defined in base CLASS. The functions can be REDEFINED in derived class. If redefined in derived class then it OVERRIDES the base class function definition.

Right option is (B) Prototype must be same in BASE class and derived class

The EXPLANATION is: The prototype must be the same. Because the function is to be OVERRIDDEN in the derived class. If the function prototype is different in derived class then it will not override the base class function and hence virtual function concept won’t work here.

Right CHOICE is (b) Public

For explanation: The VIRTUAL functions must be defined in public section of a class. This is to ensure that the virtual function is available EVERYWHERE in the program. ALSO to avoid any error while RESOLVING the method.

Correct option is (C) Runtime

Easy EXPLANATION - The resolving of virtual functions that are to be CALLED is done at run time. The base class and the derived classes may contain DIFFERENT definitions and different variables, so all these THINGS are resolved at run time and decided which function is to be called.

The correct CHOICE is (d) BASE CLASS

The best EXPLANATION: The VIRTUAL function should be declared in base class. So that when the derived class inherits from the base class, the functions can be differentiated from the one in base class and another in derived class.

The correct CHOICE is (a) virtual

To explain I would say: The virtual KEYWORD is used to declare virtual functions. Anonymous keyword is used with CLASSES and have a different meaning. The virtual functions are used to call the INTENDED function of the derived class.

Right answer is (C) Runtime POLYMORPHISM

Best explanation: It is used to achieve runtime polymorphism. The functions which are inherited and OVERRIDDEN, so at runtime the correct function is executed. The correct function call is made from the INTENDED class.

Right answer is (a) Base, derived, derived

Easy explanation - The functions which MAY give rise to ambiguity due to INHERITANCE, can be declared virtual. So that whenever derived class object is referred using pointer or REFERENCE to the base class methods, we can still call the derived class methods using virtual FUNCTION. Hence this differentiates those methods from each other.

The correct choice is (c) Correct method is called, regardless of the type of reference used for FUNCTION call

Best explanation: It is PROPERTY of the virtual function and one of their main use. Its use ensure that the correct method is called even though it is been called from different POINTER or REFERENCES. This also decreases chance of mistakes in PROGRAM.