MCQs – C++ Polymorphism

Q) Which is the correct declaration of pure virtual function in C++

1. virtual void func = 0;
2. virtual void func() = 0;
3. virtual void func(){0};
4. void func() = 0;

Answer: 2

virtual void func() = 0; is the correct declaration.

Q) In a class, pure virtual functions in C++ is used

1. To create an interface
2. To make a class abstract
3. To force derived class to implement the pure virtual function
4. All the above

Answer: 4

All are correct. Recommended to read abstract class in c++ with example that uses pure virtual function.

Q) Which public member of a base class cannot be inherited?

1. Constructor
2. Destructor
3. Both A & B
4. Only B

Answer: 3

In C++ constructor and destructor both cannot be inherited to child class.

Q) How many VPTR is created internally for a base class and a derived class

1. 0
2. 1
3. 2
4. 3

Answer: 2

Q) Number of virtual table created for a base and a derived class is

1. 0
2. 1
3. 2
4. 3

Answer: 3