Unit 2: Handling Pointers, Arrays and String - Practice Quiz

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

2 Which type of pointer can store the address of an object of any data type?

3 If p points to an element of an integer array, what does p + 1 generally indicate?

4 Which declaration represents a pointer to a pointer to an integer?

5 What is a dangling pointer?

6 A pointer that has not been initialized is commonly called a:

7 Which value is commonly used to indicate that a pointer does not point to a valid object?

8 A pointer declared inside a class is called a:

9 Which operator is used to access a member through a pointer to an object?

10 In a non-static member function, what does the this pointer refer to?

11 Which operator is used with an object to access a pointer to a non-static data member?

12 Which declaration creates a two-dimensional integer array with 2 rows and 3 columns?

13 Which loop structure is commonly used to process every element of a two-dimensional array?

14 What is an array of objects?

15 Which header file provides the standard C++ string class?

16 Which statement correctly defines a C++ string object containing Hello?

17 Which operator is used to assign one string object to another?

18 Which string member function adds characters to the end of a string?

19 Which string member function can remove characters from a string?

20 Which string member function inserts characters at a specified position?

21 What is printed by the following code?

int x = 4; int y = 7; int* p = &x; int& r = y; p = &y; r = x; std::cout << *p << " " << y;

22 Given double value = 6.25; void* vp = &value;, which expression correctly reads the stored value?

23 What is printed by this code?

int a[] = {3, 6, 9, 12, 15}; int* p = a + 1; std::cout << *(p + 2) - *p;

24 What is the final value of n?

int n = 5; int* p = &n; int** pp = &p; **pp += 3;

25 Which modification best prevents p from remaining a dangling pointer after the dynamically allocated object is deleted?

int* p = new int(10); delete p;

26 Which declaration creates an uninitialized pointer that may contain an indeterminate address?

27 Consider the overloads void show(int); and void show(int*);. Which call unambiguously selects the pointer overload in modern C++?

28 A class owns an int* data allocated with new int. Why may the compiler-generated copy constructor be unsafe?

29 Given Student s; Student* p = &s;, which statement calls the member function display() through p?

30 Which constructor body correctly assigns the parameter value to a data member that is also named value?

class Item { int value; public: Item(int value) { /* body */ } };

31 Given struct Point { int x; }; Point pt{8}; int Point::* pm = &Point::x;, which expression obtains the value 8?

32 Given struct Box { int size; }; Box b{12}; Box* pb = &b; int Box::* member = &Box::size;, which expression changes size to 20?

33 What is printed by this code?

int a[2][3] = {{1, 2, 3}, {4, 5, 6}}; int sum = 0; for (int i = 0; i < 2; ++i) sum += a[i][i + 1]; std::cout << sum;

34 A class contains int matrix[3][4];. Which nested-loop bounds correctly process every element exactly once?

35 What is the final value of total?

class Item { public: int price; Item() : price(5) {} }; Item items[4]; int total = 0; for (const Item& x : items) total += x.price;

36 Which declaration correctly creates three Book objects using a constructor Book(std::string, int)?

37 What is printed by the following code?

std::string s = "programming"; std::cout << s.substr(3, 4);

38 What does std::string::find return when the requested substring is absent?

39 What is the value of s after this code executes?

std::string s(3, 'A'); std::string t = "BC"; s = s + t;

40 What is the final value of s?

std::string s = "abcdef"; s.erase(2, 2); s.insert(2, "XY");

41 Given int a = 10, b = 20; int* p = &a; int& r = a;, which statement sequence changes a to 20 and then makes p point to b without changing what r refers to?

42 What is the correct way to print the value stored in int n = 42; void* vp = &n;?

43 For int a[5] = {2, 4, 6, 8, 10}; int* p = a + 1;, which expression evaluates to 8?

44 For int a[5] = {2, 4, 6, 8, 10}; int* p = a + 1;, which expression evaluates to 8?

45 What is printed by int x = 5; int* p = &x; int** q = &p; **q = 9; std::cout << x;?

46 Which modification prevents undefined behavior in this code after the block ends? int* p; { int x = 7; p = &x; } std::cout << *p;

47 Which declaration creates a wild pointer whose value is indeterminate until it is initialized?

48 After int* p = nullptr;, which operation is well-defined?

49 Consider class A { int* p; public: A(int v) : p(&v) {} int get() const { return *p; } };. What is the fundamental defect?

50 Given class C { public: int n; void f() { n += 2; } }; C obj; C* p = &obj;, which expression correctly invokes f through p?

51 Inside a non-static member function, what does this represent?

52 For struct S { int x; }; int S::* pm = &S::x; S s{12};, which expression evaluates to 12?

53 For void f(int a[][3], int rows), which statement about passing int m[2][3] to f(m, 2) is correct?

54 Inside class Matrix, a member is declared as int a[2][3];. Which definition correctly initializes all elements through a constructor initializer list?

55 Given class B { public: B(); B(int); }; B a[3] = {B(1), B(2)};, what is required for this declaration to be valid?

56 For std::string s = "abc";, which operation has linear worst-case complexity in the current string length?

57 What is the result of std::string s = "ABCDE"; std::string t(s, 1, 3); s = t;?

58 What does std::string s = "abcdef"; s.erase(2, 2); produce?

59 What is the final value of std::string s = "one two"; s.replace(4, 3, "three");?

60 For std::string s = "a,b,,c";, which expression returns the position of the second comma?