Object Oriented Programming interview questions part 15
Object Oriented Programming interview questions part 15
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Total Questions: 20
1. When is the destructor of a global object called?
Correct Answer is : Just before end of program
2. How the constructors and destructors can be differentiated?
Correct Answer is : Destructors are preceded with a tilde (~) symbol, and constructor doesn’t
3. Destructors doesn’t accept parameters.
Correct Answer is : TRUE
4. Destructors can be ________
Correct Answer is : Virtual
5. Global destructors execute in ___________ order after main function is terminated
Correct Answer is : Reverse
6. When is it advised to have user defined destructor?
Correct Answer is : When class contains some pointer to memory allocated in class
7. Which among the following is correct for destructors concept?
Correct Answer is : There can be only one destructor in a class
8. Which class destructor will be called first, when following code go out of scope? class A{ }; class B{ }; class C: public B{ }; A a; B b; C c;
Correct Answer is : ~C()
9. When an object is passed to a function, its copy is made in the function and then:
Correct Answer is : The destructor of the copy is called when function is returned
10. What happens when an object is passed by reference?
Correct Answer is : Destructor is not called
11. What is downcasting?
Correct Answer is : Casting supertype to subtype
12. Which among the following is a mandatory condition for downcasting?
Correct Answer is : It must be done explicitly
13. Downcasting is _______________________
Correct Answer is : Never safe
14. Downcasting ____________________
Correct Answer is : Can result in unexpected results
15. What should be used for safe downcast?
Correct Answer is : Dynamic cast
16. What does dynamic_cast return after successful type casting?
Correct Answer is : Address of object which is converted
17. If dynamic_cast fails, which value is returned?
Correct Answer is : null pointer
18. Which is the proper syntax of dynamic_cast?
Correct Answer is : dynamic_cast(object)
19. Which is the exception handler for the exceptions of downcasting?
Correct Answer is : ClassCastException
20. How to prevent the ClassCastExceptions?
Correct Answer is : By using instanceof
