Free Test Pure virtual functions... – C++ Lan...

Q1: What is a pure virtual function in C++?

A. A function declared with = 0 and has no implementation B. A function that must be static C. A function implemented in the base class D. A function only for constructors

Q2: What is an abstract class?

A. A class that cannot be instantiated and has at least one pure virtual function B. A class without any functions C. A class with only static members D. A class with private constructors

Q3: Why use pure virtual functions?

A. To enforce derived classes to implement them B. To allow objects creation C. To hide implementation D. To speed up execution

Q4: Can an abstract class have a constructor?

A. Yes, to initialize base class parts B. No, constructors are not allowed C. Only if pure virtual destructor D. Only static constructors

Q5: Can a pure virtual function have an implementation?

A. Yes, it can have a body B. No, never C. Only in derived classes D. Only if static

Q6: What happens if a derived class does not implement all pure virtual functions?

A. Derived class becomes abstract B. Compilation error C. Program runs with warnings D. Derived class functions are auto-generated

Q7: Can you create an object of an abstract class?

A. No, abstract classes cannot be instantiated B. Yes, directly C. Only through pointers D. Only for static classes

Q8: What keyword is used to declare a pure virtual function?

A. = 0 B. virtual C. override D. abstract

Q9: What is the primary use of abstract classes?

A. To provide interface and base class functionality B. To speed up execution C. To store static data D. To prevent inheritance

Q10: Can abstract classes contain non-pure virtual functions?

A. Yes, they can contain both B. No, only pure virtual functions C. Only static functions D. Only constructors

Q11: Which of these makes a class abstract?

A. Having at least one pure virtual function B. Having no functions C. Having only static members D. Having private constructors

Q12: Are pure virtual destructors allowed?

A. Yes, but must have an implementation B. No, destructors cannot be pure virtual C. Only in derived classes D. Only if inline

Q13: What is the role of a pure virtual destructor?

A. To make the class abstract and ensure cleanup B. To speed up destruction C. To prevent inheritance D. To optimize memory

Q14: Can pure virtual functions be overloaded?

A. Yes, like any other virtual function B. No, they cannot C. Only in base classes D. Only if static

Q15: Which of these is true about abstract classes?

A. They cannot be instantiated B. They are always final C. They have no data members D. They have no member functions

Q16: How are pure virtual functions implemented?

A. By derived classes overriding them B. By base class only C. By the compiler D. By friend classes

Q17: What happens if you try to instantiate an abstract class?

A. Compilation error B. Runs but throws runtime error C. Creates a pointer only D. Creates a default object

Q18: Can abstract classes have constructors?

A. Yes, to be called by derived classes B. No, constructors are disallowed C. Only static constructors D. Only virtual constructors

Q19: Is it possible to provide implementation for a pure virtual function?

A. Yes, but it must be explicitly defined outside the class B. No, never C. Only in derived classes D. Only if inline

Quiz for Pure virtual functions and abstract classes