41. Which of these is not a valid C++ arithmetic operator?
- a) +
- b) *
- c) ^
- d) #
Answer: D - # is the preprocessor operator, not an arithmetic operator.
42. What is the correct syntax to declare a namespace in C++?
- a) namespace MyNamespace { }
- b) class MyNamespace { }
- c) package MyNamespace { }
- d) module MyNamespace { }
Answer: A - Namespaces are declared using the namespace keyword.
43. Which of the following is true about function templates?
- a) They must have exactly one template parameter
- b) They generate different functions at compile time
- c) They cannot be overloaded
- d) They must return void
Answer: B - Templates generate specialized functions at compile time based on usage.
44. What is the output of: cout << (5 & 3);
- a) 0
- b) 1
- c) 7
- d) 8
Answer: B - Bitwise AND of 5 (101) and 3 (011) is 1 (001).
45. Which of these is not a valid C++11 smart pointer?
- a) unique_ptr
- b) shared_ptr
- c) auto_ptr
- d) weak_ptr
Answer: C - auto_ptr is deprecated in C++11.
46. What is the purpose of the 'override' keyword?
- a) To indicate a function overrides a base class virtual function
- b) To prevent function overriding
- c) To optimize virtual function calls
- d) To create multiple function versions
Answer: A - override explicitly indicates a virtual function override.
47. Which STL container uses a hash table implementation?
- a) vector
- b) map
- c) unordered_map
- d) set
Answer: C - unordered_map uses hash table implementation.
48. What is the correct way to declare a constant pointer?
- a) const int *ptr;
- b) int const *ptr;
- c) int * const ptr;
- d) const int const *ptr;
Answer: C - int * const ptr declares a constant pointer to int.
49. Which of these is not a valid C++ cast operator?
- a) static_cast
- b) dynamic_cast
- c) reinterpret_cast
- d) safe_cast
Answer: D - safe_cast is not a standard C++ cast operator.
50. What is the output of: cout << sizeof("Hello");
- a) 5
- b) 6
- c) 8
- d) Depends on system
Answer: B - Includes 5 characters plus null terminator.
51. Which of these is not a valid C++11 feature?
- a) auto keyword
- b) range-based for loops
- c) concepts
- d) nullptr
Answer: C - Concepts were introduced in C++20.
52. What is the purpose of the 'final' keyword?
- a) To prevent class inheritance
- b) To prevent method overriding
- c) Both a and b
- d) To mark the last element in a container
Answer: C - final can prevent inheritance or overriding.
53. Which STL algorithm is used to reverse a container?
- a) std::sort
- b) std::reverse
- c) std::rotate
- d) std::flip
Answer: B - std::reverse reverses elements in a range.
54. What is the correct way to declare a lambda function?
- a) [](int x) { return x * x; }
- b) lambda(int x) { return x * x; }
- c) function(int x) { return x * x; }
- d) auto f = (int x) => x * x;
Answer: A - Lambda syntax uses [] for capture list.
55. Which of these is not a valid C++20 feature?
- a) Concepts
- b) Modules
- c) Ranges
- d) Properties
Answer: D - Properties are not part of standard C++20.
56. What is the output of: cout << (5 | 3);
- a) 1
- b) 7
- c) 8
- d) 15
Answer: B - Bitwise OR of 5 (101) and 3 (011) is 7 (111).
57. Which of these is not a valid C++ container?
- a) vector
- b) array
- c) list
- d) tuple
Answer: D - tuple is not a container (it's a fixed-size heterogeneous collection).
58. What is the purpose of the 'decltype' keyword?
- a) To declare variables
- b) To determine the type of an expression
- c) To delete types
- d) To declare template parameters
Answer: B - decltype deduces the type of an expression at compile time.
59. Which STL algorithm is used to find an element?
- a) std::search
- b) std::find
- c) std::locate
- d) std::get
Answer: B - std::find searches for a value in a range.
60. What is the correct way to declare a thread in C++11?
- a) std::thread t(function);
- b) thread t(function);
- c) new std::thread(function);
- d) std::thread t = function;
Answer: A - std::thread constructor takes a callable object.