C++ Practice & Interview Zone

 

Multiple Choice Questions

 

1. What is the correct syntax to declare a class in C++?
   a) class myClass { };
   b) Class myClass { }
   c) class myClass;
   d) struct myClass { };
   Answer: a

 

2. What is the default access specifier for members of a class in C++?
   a) protected
   b) private
   c) public
   d) static
   Answer: b

 

3. Which of the following is used to dynamically allocate memory in C++?
   a) malloc
   b) alloc
   c) new
   d) calloc
   Answer: c

 

4. Which operator is used to resolve scope in C++?
   a) ::
   b) .
   c) ->
   d) :
   Answer: a

 

5. What is the output of this code?

int x = 5;

cout << x++;

1. a) 6
   b) 5
   c) Error
   d) Undefined
   Answer: b
2. Which keyword is used to inherit a class in C++?
   a) inherit
   b) extends
   c) public
   d) using
   Answer: c

 

7. What will this code output?

int x = 10;

int* p = &x;

cout << *p;

1. a) address of x
   b) garbage
   c) 10
   d) Error
   Answer: c

 

8. Which constructor is called when an object is created without arguments?
   a) Copy constructor
   b) Default constructor
   c) Parameterized constructor
   d) Virtual constructor
   Answer: b

 

9. Destructor name is same as constructor but prefixed with:
   a) *
   b) &
   c) ~
   d) #
   Answer: c

 

10. Which feature allows same function name with different arguments?
    a) Operator Overloading
    b) Function Overriding
    c) Function Overloading
    d) Inheritance
    Answer: c

 

11. What does STL stand for in C++?
    a) Standard Testing Library
    b) Standard Template Library
    c) System Template Language
    d) Source Template Library
    Answer: b

 

12. Which of the following is not a container in STL?
    a) vector
    b) list
    c) map
    d) math
    Answer: d

 

13. What is used to handle exceptions in C++?
    a) if-else
    b) try-catch
    c) switch
    d) error handler
    Answer: b

 

14. Which of these is a smart pointer in C++11?
    a) auto_ptr
    b) unique_ptr
    c) dynamic_ptr
    d) shared_obj
    Answer: b

 

15. What is the size of int on most 32-bit systems?
    a) 2 bytes
    b) 4 bytes
    c) 8 bytes
    d) 1 byte
    Answer: b

 

16. Function templates are used for:
    a) memory management
    b) exception handling
    c) generic programming
    d) runtime polymorphism
    Answer: c

 

17. Virtual functions are resolved at:
    a) Compile time
    b) Link time
    c) Run time
    d) Preprocessing
    Answer: c

 

18. Which container does not allow duplicate keys?
    a) multimap
    b) vector
    c) set
    d) multiset
    Answer: c

 

19. this pointer in C++ refers to:
    a) base class
    b) derived class
    c) current object
    d) none
    Answer: c

 

20. What is the output of this code?

int a = 4, b = 3;

cout << a % b;

1. a) 0
   b) 1
   c) 2
   d) Error
   Answer: b

 

21. Which of the following is a reference operator?
    a) *
    b) &
    c) %
    d) @
    Answer: b

 

22. Which keyword is used to define constant variables?
    a) static
    b) const
    c) define
    d) final
    Answer: b

 

23. What is the role of #include in C++?
    a) Compilation
    b) Linking
    c) Header file inclusion
    d) Debugging
    Answer: c

 

24. What will be the output?

cpp

CopyEdit

string s = “Hello”;

cout << s.length();

1. a) 4
   b) 5
   c) 6
   d) Error
   Answer: b

 

25. Which header is required for file handling?
    a) <iostream>
    b) <fstream>
    c) <stdlib.h>
    d) <stdio.h>
    Answer: b

 

26. Which of the following is used for multithreading?
    a) <thread>
    b) <pthread>
    c) <mutex>
    d) <threads>

Answer: a

 

27. Which preprocessor directive is used to define macros?
    a) #define
    b) #macro
    c) #include
    d) #typedef
    Answer: a

 

28. Lambda expressions were introduced in which version of C++?
    a) C++98
    b) C++03
    c) C++11
    d) C++20
    Answer: c

 

29. Which is not a valid iterator type in STL?
    a) forward_iterator
    b) backward_iterator
    c) random_access_iterator
    d) bidirectional_iterator
    Answer: b

 

30. Which is used to allocate memory from heap in C++?
    a) new
    b) malloc
    c) calloc
    d) all of the above
    Answer: d

 

31. typeid is used for:
    a) templates
    b) type casting
    c) type checking at runtime
    d) exception handling
    Answer: c

 

32. What will the following code return?

cout << sizeof(char);

1. a) 2
   b) 4
   c) 1
   d) 8
   Answer: c

 

33. What is the correct syntax of namespace in C++?
    a) namespace name { }
    b) namespace : name { }
    c) namespace => name { }
    d) namespace(name) { }
    Answer: a

 

34. A class containing at least one pure virtual function is called:
    a) base class
    b) abstract class
    c) virtual class
    d) polymorphic class
    Answer: b

 

35. How many catch blocks can you have for a try block?
    a) 1
    b) 2
    c) As many as needed
    d) Only one
    Answer: c

 

36. What is std::pair used for?
    a) Sorting
    b) Memory
    c) Storing two values
    d) File I/O
    Answer: c

 

37. Which header file is used for vectors?
    a) <vector>
    b) <list>
    c) <map>
    d) <array>
    Answer: a

 

38. Which C++11 feature allows you to deduce variable type?
    a) const
    b) auto
    c) static
    d) volatile
    Answer: b

 

39. Which STL container follows FIFO?
    a) stack
    b) queue
    c) vector
    d) map
    Answer: b

 

40. unique_ptr belongs to which header?
    a) <memory>
    b) <utility>
    c) <thread>
    d) <pointer>
    Answer: a