Unit 1: Principles of OOP and C++ Essentials - Practice Quiz

1 What is the primary focus of object-oriented programming?

2 Which programming paradigm primarily organizes a program as a sequence of functions?

3 Which C++ stream object is commonly used to display output on the console?

4 Which operator is used with cin to read input in C++?

5 What is a class in C++?

6 What is an object in C++?

7 How are the data members of a union stored?

8 Which statement correctly describes the members of a structure?

9 What does an enumeration define in C++?

10 Which keyword declares a scoped enumeration in modern C++?

11 How many copies of a static data member are shared by all objects of a class?

12 Which type of class function can be called using the class name without creating an object?

13 What is a user-defined function?

14 Which keyword requests that a function be treated as an inline function?

15 Which keyword declares a non-member function that can access a class's private members?

16 What privilege does a friend class receive?

17 Which symbol is used to declare a reference variable in C++?

18 What is passed to a function in call by value?

19 Which kind of parameter is normally used in call by address?

20 What is recursion?

21 A banking application must represent accounts with their balances and restrict balance updates to validated deposit and withdrawal operations. Which design best follows the object-oriented paradigm?

22 What does the following code print?

int x = 7;

cout << setfill('0') << setw(4) << x;

23 After cin >> age;, a program must read a full name using getline(cin, name);. However, name becomes empty. Which statement should normally be placed before getline?

24 Consider the following class:

class Box { int width; public: void setWidth(int w) { width = w; } };

Which statement about width is correct?

25 What is printed by this program fragment?

class Item { public: Item() { cout << "C"; } };

Item items[3];

26 A program must store an employee's integer ID, floating-point salary, and character grade simultaneously. Which declaration is most appropriate?

27 Given enum class Status { Idle, Running, Stopped };, which statement correctly creates a variable initialized to Running?

28 What is printed by the following code?

class Counter { public: static int count; Counter() { ++count; } };

int Counter::count = 0;

Counter a[3]; Counter b; cout << Counter::count;

29 A class contains a non-static member value and a static member count. Which operation is valid inside a static member function without receiving an object?

30 Given int power(int base, int exponent = 2);, which call uses the default argument?

31 Which pair of function declarations forms a valid overload based on parameter types?

32 Consider inline int square(int x) { return x * x; }. If int i = 3; cout << square(i++) << " " << i; is executed, what is printed?

33 A non-member function must compare private values stored in two objects of class Box. Which declaration inside Box grants the required access?

34 If class A declares class B as a friend, which statement is correct?

35 What is printed by this code?

int x = 4, y = 9;

int& larger = (x > y) ? x : y;

larger = 0;

cout << x << " " << y;

36 Which declaration correctly creates a reference variable that aliases score?

37 What is printed after this function call?

void update(int v, int* p, int& r) { ++v; ++(*p); ++r; }

int a = 1, b = 1, c = 1; update(a, &b, c); cout << a << b << c;

38 Which function signature allows two integers to be swapped without pointer syntax at the call site?

39 What value is returned by sumOdd(5)?

int sumOdd(int n) { if (n <= 1) return 1; return n + sumOdd(n - 2); }

40 What does the following call print?

void show(int n) { if (n == 0) return; cout << n; show(n - 1); cout << n; }

show(3);

41 A program represents bank accounts as records and provides separate functions such as deposit(Account&, double) and withdraw(Account&, double). Which redesign most strongly demonstrates object-oriented encapsulation rather than merely reorganizing the procedural code?

42 Given int x; while (std::cin >> x) { /* process x */ }, what is the most accurate reason the loop terminates?

43 What is the key language-level distinction between these declarations: class A { int x; }; and struct B { int x; };?

44 Consider union U { int i; float f; }; U u; u.i = 10; u.f = 2.5f;. Which statement is correct?

45 Which initialization is rejected when enum class State { Idle, Busy }; is declared?

46 For class Counter { static int n; };, which definition is required in a traditional pre-C++17 translation unit if n is odr-used?

47 Inside a static member function of class Logger, which access is invalid unless an object is explicitly supplied?

48 Given void f(int); void f(double = 1.0);, what happens for the call f()?

49 Which statement best describes the inline specifier in modern C++?

50 If class Box { friend void inspect(const Box&); private: int value; }; is declared, which statement is correct?

51 Class A declares friend class B;. Which conclusion is valid?

52 After int a = 3, b = 4; int& r = a; r = b;, what are the final values?

53 Which declaration is valid and safely extends the lifetime of the temporary bound to it?

54 For void f(int x, int* p, int& r) { x++; (*p)++; r++; }, called as int a=1,b=1; f(a,&a,b);, what are a and b afterward?

55 Which call can be valid for void change(int* p) while still allowing the function to represent "no object supplied"?

56 What is the principal defect in int sum(int n) { return n + sum(n - 1); } when called with a positive integer?

57 What does this function return for f(4)? int f(int n) { if (n <= 1) return 1; return f(n - 1) + f(n - 2); }

58 After std::cin >> n; std::getline(std::cin, line);, why can line initially be empty when valid input is entered on one line?

59 For enum Color { Red = 1, Green, Blue = 1 };, which statement is correct?

60 A class has a non-static member int value; but no user-declared constructor. What happens for Record r; when Record is an aggregate and default initialization is used?