Quiz for Virtual destructors

Q1: Why should destructors be declared virtual in base classes?

A. To ensure derived class destructors are called B. To prevent object instantiation C. To make the class abstract D. To optimize performance

Q2: What happens if a base class destructor is not virtual?

A. Derived class destructor is not called B. Program crashes C. Compilation error D. Derived class destructor is always called

Q3: Can a destructor be both virtual and pure virtual?

A. Yes, it can B. No, destructors cannot be pure virtual C. Only in abstract classes D. Only in derived classes

Q4: Why is it important to declare the destructor virtual in a polymorphic base class?

A. To avoid undefined behavior B. To speed up destruction C. To prevent inheritance D. To avoid static binding

Q5: What is a polymorphic base class?

A. A class with at least one virtual function B. A class without virtual functions C. An abstract class D. A class with no member functions

Q6: When should you declare a virtual destructor?

A. If the class is intended to be used polymorphically B. Only for abstract classes C. Only for classes with no data members D. Never

Q7: What does a virtual destructor ensure?

A. Derived class destructors are called during object destruction B. Derived class constructors are called C. Prevents object copying D. Forces static binding

Q8: Can a class have a virtual destructor but no other virtual functions?

A. Yes, it can B. No, it cannot C. Only if it is abstract D. Only if it is final

Q9: What keyword is used to declare a virtual destructor?

A. virtual B. inline C. friend D. static

Q10: What happens if a derived class destructor is not explicitly defined?

A. Base class destructor will still be called properly B. Program crashes C. Compilation error D. Destructor is not called

Q11: Are destructors inherited?

A. Yes, destructors are inherited but can be overridden B. No, destructors are not inherited C. Only if virtual D. Only in abstract classes

Q12: What happens if you delete a derived object through a base pointer without a virtual destructor?

A. Only base destructor is called, causing resource leaks B. Both destructors called C. Program compiles with warning D. Program crashes immediately

Q13: Can a virtual destructor have a definition outside the class?

A. Yes, it can B. No, it must be inline C. Only for abstract classes D. Only if pure virtual

Q14: Is it mandatory to declare destructor virtual in classes not intended for inheritance?

A. No, only if inheritance is expected B. Yes, always C. Only for abstract classes D. Only for final classes

Q15: What is the effect of declaring a destructor pure virtual?

A. Makes the class abstract but still requires a destructor implementation B. Destructor cannot be pure virtual C. Destructor is deleted D. Destructor does nothing

Q16: Which of these is true about virtual destructors?

A. They support proper cleanup of polymorphic objects B. They prevent inheritance C. They improve performance D. They disable virtual functions

Q17: Does virtual destructor affect object size?

A. Yes, adds to vtable pointer size B. No effect C. Reduces object size D. Makes object static

Q18: Which of these statements is correct?

A. A virtual destructor ensures the most derived destructor is called B. A virtual destructor disables polymorphism C. A virtual destructor is optional for polymorphic classes D. Virtual destructors cannot be overridden

Q19: What happens if virtual destructor is missing but base class pointer deletes derived object?

A. Undefined behavior B. Safe deletion C. Compilation error D. Warning only

Q20: Which of the following best practices is recommended?

A. Always declare destructors virtual in base classes intended for inheritance B. Never declare destructors virtual C. Declare all functions virtual D. Use inline destructors only