BCA 2nd Sem -Object Oriented Programming Using C++ UNIT-IV MCQ

BCA 2nd Sem -Object Oriented Programming Using C++ UNIT-IV MCQ

UNIT-I

-Introducing Object Oriented Approach -Relating to other paradigms {Functional, Data decomposition} - Basic terms and ideas Abstraction, Encapsulation, Inheritance, Polymorphism - - Review of C -Difference between C and C++ - cin, cout, new, delete, operators
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Unit-1 MCQ's

UNIT-II

- Classes and Objects Encapsulation -information hiding, - abstract data types, -Object & classes -attributes -methods -C++ class declaration -State idendity and behaviour of an object -Constructors and destructors, -instantiation of objects, -Default parameter value, -object types, -C++ garbage collection, -dynamic memory allocation, -abstract classes.

Unit-2 MCQ's

UNIT-III

- Inheritance and Polymorphism Inheritance, -Class hierarchy, -derivation – public, private & protected, -Aggregation, - composition vs classification hierarchies, -Polymorphism, -Categorization of polymorphism techniques, -Method polymorphism, - Operator overloading

Unit-3 MCQ's

UNIT-IV

-Generic function Template function, -function name overloading, -Overriding inheritance methods, -Run time polymorphism, -Multiple Inheritance

Unit-4 MCQ's

UNIT-V

- Files and Exception Handling Streams and files, - Exception handling

Unit-5 MCQ's

Object Oriented Programming Using C++

1. What is a template function in C++?

a) A function that can accept only integer arguments
b) A function that can work with different data types
c) A function that cannot return any value
d) A function with a fixed return type
Answer: b) A function that can work with different data types

2. Which keyword is used to define a template function in C++?

a) `template`
b) `generic`
c) `typename`
d) `class`
Answer: a) `template`

3. What is the correct syntax for defining a function template?

a) `template <typename T> T func(T a, T b);`
b) `generic <class T> T func(T a, T b);`
c) `class <typename T> T func(T a, T b);`
d) `template generic <T> T func(T a, T b);`
Answer: a) `template <typename T> T func(T a, T b);`

4. What is the primary purpose of function templates?

a) To write multiple functions with different names
b) To allow a single function to handle multiple data types
c) To improve memory allocation
d) To replace pointers in C++
Answer: b) To allow a single function to handle multiple data types

5. How do we define multiple template parameters in a function template?

a) `template <class T, class U>`
b) `template (class T, class U)`
c) `template {class T, class U}`
d) `template [class T, class U]`
Answer: a) `template <class T, class U>`

6. What is the difference between `typename` and `class` in templates?

a) `class` is used only for classes, while `typename` is for primitive types
b) There is no difference; both can be used interchangeably
c) `typename` is required for non-type template parameters
d) `class` is preferred in C++17, while `typename` is outdated
Answer: b) There is no difference; both can be used interchangeably

7. Which of the following is TRUE about function templates?

a) Function templates must have at least one parameter
b) Function templates can only return `void`
c) Function templates allow writing generic code for multiple types
d) Function templates cannot be overloaded
Answer: c) Function templates allow writing generic code for multiple types

8. How is a function template instantiated?

a) Automatically when it is called with a specific data type
b) Manually using the `new` keyword
c) By defining it inside a class
d) Using the `class` keyword
Answer: a) Automatically when it is called with a specific data type

9. What happens if a function template is called with a data type that it does not support?

a) The compiler generates an error
b) The function executes with a default type
c) The program crashes at runtime
d) The function ignores the unsupported data type
Answer: a) The compiler generates an error

10. Can function templates be overloaded?

a) No, function templates cannot be overloaded
b) Yes, but only with non-template functions
c) Yes, function templates can be overloaded
d) Only in C++17 and later versions
Answer: c) Yes, function templates can be overloaded

11. What is the correct way to call a function template explicitly?

a) `func<int>(10, 20);`
b) `func<int, 10, 20>;`
c) `func(10, 20) <int>;`
d) `func<int> {10, 20};`
Answer: a) `func<int>(10, 20);`

12. What is a non-type template parameter?

a) A template parameter that is a constant value instead of a type
b) A template parameter that only supports integer types
c) A template parameter that stores function pointers
d) A template parameter used in virtual functions
Answer: a) A template parameter that is a constant value instead of a type

13. Can function templates return a value?

a) Yes, they can return any data type
b) No, they always return `void`
c) Yes, but only integer values
d) Only if they use `static` keyword
Answer: a) Yes, they can return any data type

14. What is template specialization?

a) A technique to provide a specific implementation for a particular data type
b) A way to declare multiple templates in one function
c) A feature used for operator overloading
d) A method for dynamic memory allocation
Answer: a) A technique to provide a specific implementation for a particular data type

15. Can a function template have a default parameter?

a) Yes, it can have default parameters
b) No, default parameters are not allowed in templates
c) Only if the function is inline
d) Only if it is a non-member function
Answer: a) Yes, it can have default parameters

16. What is the correct way to define a function template for swapping two values?


template <typename T>
void swapValues(T &a, T &b) {
    T temp = a;
    a = b;
    b = temp;
}


void swapValues(T a, T b) {
    T temp = a;
    a = b;
    b = temp;
}


template swapValues(T a, T b) {
    T temp = a;
    a = b;
    b = temp;
}


class T swapValues(T a, T b) {
    T temp = a;
    a = b;
    b = temp;
}

Answer: a)

17. What is function template instantiation?

a) Creating a specific version of the template function for a given data type
b) Deleting a function template from memory
c) Overloading a function template
d) Using a function template inside a class
Answer: a) Creating a specific version of the template function for a given data type

18. Can a function template have multiple parameters of different types?

a) Yes
b) No
Answer: a) Yes

19. What is the advantage of using function templates?

a) Reduces code duplication
b) Increases memory usage
c) Slows down program execution
d) Complicates debugging
Answer: a) Reduces code duplication

20. What happens if a function template is not used in a program?

a) The compiler does not generate any code for it
b) The compiler generates a warning
c) The program crashes
d) The function template gets deleted automatically
Answer: a) The compiler does not generate any code for it

21. Which of the following statements is true about function templates?

a) They can only be defined in the `main()` function.
b) They can have multiple template parameters.
c) They cannot be overloaded.
d) They must always return `void`.
Answer: b) They can have multiple template parameters.

22. What happens if a function template is defined but never used in a program?

a) The compiler will generate an error.
b) The function will still be compiled and added to the executable.
c) The function template will not be instantiated.
d) The linker will remove it during optimization.
Answer: c) The function template will not be instantiated.

23. What is the correct syntax for using a template function explicitly for `double` type?

a) `func<double>(10.5, 20.5);`
b) `func(10.5, 20.5)<double>;`
c) `func<double>{10.5, 20.5};`
d) `func(double 10.5, double 20.5);`
Answer: a) `func<double>(10.5, 20.5);`

24. Can a function template accept both template and non-template parameters?

a) Yes
b) No
Answer: a) Yes

25. What does the following function template do?

template <typename T>
T square(T x) {
    return x * x;
}

a) Squares the given value of any data type
b) Returns the square root of the input
c) Multiplies x by itself only if x is an integer
d) Causes a compilation error
Answer: a) Squares the given value of any data type

26. Which of the following is true about function templates?

a) They reduce code duplication.
b) They increase compilation time.
c) They cannot be used for user-defined types.
d) They require explicit specialization for all types.
Answer: a) They reduce code duplication.

27. Can function templates be used with user-defined types like `struct` or `class`?

a) Yes
b) No
Answer: a) Yes

28. What is an explicit specialization of a function template?

a) Providing a specific implementation for a certain data type.
b) Using `explicit` keyword inside a template function.
c) Making a function template `private`.
d) Preventing a function template from being instantiated.
Answer: a) Providing a specific implementation for a certain data type.

29. What is an advantage of using function templates?

a) They allow generic programming.
b) They eliminate the need for function overloading.
c) They improve code reusability.
d) All of the above.
Answer: d) All of the above.

30. What does this code do?

template <class T>
T add(T a, T b) {
    return a + b;
}
int main() {
    cout << add(10, 20) << endl;
}

a) Prints 30
b) Causes a runtime error
c) Prints 1020
d) Causes a compilation error
Answer: a) Prints 30

31. What happens when a function template is instantiated with different data types?

a) The compiler generates a separate function for each type.
b) The same function instance is used for all data types.
c) The template cannot be instantiated with different types.
d) It results in an error.
Answer: a) The compiler generates a separate function for each type.

32. What is function template overloading?

a) Defining multiple function templates with different parameter lists.
b) Using multiple templates inside a single function.
c) Calling a function template multiple times.
d) Using `#define` macros instead of templates.
Answer: a) Defining multiple function templates with different parameter lists.

33. What is the main difference between function overloading and function templates?

a) Function overloading requires multiple definitions, whereas templates generate them automatically.
b) Function templates are faster than function overloading.
c) Function overloading works only for primitive data types.
d) Function templates always return `void`.
Answer: a) Function overloading requires multiple definitions, whereas templates generate them automatically.

34. Which of the following can be a non-type template parameter?

a) `int`
b) `char`
c) `bool`
d) All of the above
Answer: d) All of the above

35. Which of the following is an invalid function template declaration?

a) `template <class T> T func(T a, T b);`
b) `template <typename T> void print(T a);`
c) `template (class T) T sum(T a, T b);`
d) `template <class T, class U> T add(T a, U b);`
Answer: c) `template (class T) T sum(T a, T b);`

36. Can we create a template function inside a class?

a) Yes
b) No
Answer: a) Yes

37. How can we restrict a function template to work with only integer types?

a) Using `enable_if` or explicit specialization
b) Using the `restrict` keyword
c) It is not possible
d) Using `const` keyword
Answer: a) Using `enable_if` or explicit specialization

38. Can function templates be recursive?

a) Yes
b) No
Answer: a) Yes

39. What happens if a function template has a static variable?

a) Each instantiation gets its own copy of the variable.
b) The same static variable is shared among all instances.
c) The function cannot be instantiated.
d) Causes a compilation error.
Answer: a) Each instantiation gets its own copy of the variable.

40. What is a variadic template function?

a) A template function that can accept a variable number of arguments.
b) A template function that returns a `void` type.
c) A template function that only works with integer types.
d) A template function that must be explicitly specialized.
Answer: a) A template function that can accept a variable number of arguments.

41. What is function overloading in C++?

a) Defining multiple functions with the same name but different parameters.
b) Defining multiple functions with the same name and same parameters.
c) Using virtual functions in derived classes.
d) Defining a function more than once in the same scope.
Answer: a) Defining multiple functions with the same name but different parameters.

42. What must be different in overloaded functions?

a) Return type
b) Function name
c) Number or type of parameters
d) All of the above
Answer: c) Number or type of parameters

43. Can function overloading be based only on return type?

a) Yes
b) No
Answer: b) No

44. What is the correct way to overload functions?

int add(int a, int b);
float add(float a, float b);

int add(int a, int b);
int add(int x, int y);

int add(int a, int b);
int add(int a, float b);

d) Both (a) and (c)
Answer: d) Both (a) and (c)

45. What will happen if two functions have the same name and same parameters?

a) Compile-time error
b) Runtime error
c) Overloading will work normally
d) The program will not compile
Answer: a) Compile-time error

46. Which of the following is an example of valid function overloading?

void show(int a);
void show(double b);

int show(int a);
void show(int a);

void show(int a);
void show(int a, int b);

d) Both (a) and (c)
Answer: d) Both (a) and (c)

47. Function overloading is an example of:

a) Dynamic polymorphism
b) Static polymorphism
c) Encapsulation
d) None of the above
Answer: b) Static polymorphism

48. What is the main advantage of function overloading?

a) Improves readability
b) Reduces execution time
c) Reduces memory consumption
d) None of the above
Answer: a) Improves readability

49. Can constructors be overloaded in C++?

a) Yes
b) No
Answer: a) Yes

50. Can destructors be overloaded in C++?

a) Yes
b) No
Answer: b) No

51. What happens if overloaded functions have default arguments?

a) Compilation error
b) The compiler may face ambiguity
c) The program executes normally
d) Function overloading is not allowed with default arguments
Answer: b) The compiler may face ambiguity

52. Function overloading in C++ is resolved at:

a) Compile time
b) Runtime
c) Linking time
d) Execution time
Answer: a) Compile time

53. Can overloaded functions be defined in different classes?

a) Yes
b) No
Answer: a) Yes

54. Which function is selected when multiple overloaded functions match a call?

a) The most specific match
b) The first function in the code
c) The function with the largest parameter size
d) The function with the smallest parameter size
Answer: a) The most specific match

55. Can a base class and derived class have overloaded functions with the same name?

a) Yes
b) No
Answer: a) Yes

56. How does function overloading relate to polymorphism?

a) It is an example of runtime polymorphism
b) It is an example of compile-time polymorphism
c) It is unrelated to polymorphism
d) It depends on the implementation
Answer: b) It is an example of compile-time polymorphism

57. Which of the following cannot be overloaded?

a) Constructors
b) Destructors
c) Member functions
d) Operators
Answer: b) Destructors

58. Can function overloading be used with friend functions?

a) Yes
b) No
Answer: a) Yes

59. Function overloading depends on:

a) The number of parameters
b) The type of parameters
c) The sequence of parameters
d) All of the above
Answer: d) All of the above

60. Can overloaded functions have different return types?

a) Yes, if the function signatures are different
b) No, return type alone cannot differentiate overloaded functions
Answer: b) No, return type alone cannot differentiate overloaded functions

61. What is the role of function overloading in OOP?

a) It allows the same function name to be used for different tasks
b) It helps in runtime binding
c) It makes the code less readable
d) It does not affect code quality
Answer: a) It allows the same function name to be used for different tasks

62. In C++, which function overloading is incorrect?

void test(int);
void test(double);

int test(int);
void test(int);

void test(int, double);
void test(double, int);

d) None of the above
Answer: b)

int test(int);
void test(int);

(Overloading cannot be based only on return type)

63. Can we overload a function using a pointer as a parameter?

a) Yes
b) No
Answer: a) Yes

64. Which of the following statements is correct?

a) Function overloading decreases performance
b) Function overloading increases program complexity
c) Function overloading makes a program easier to read and maintain
d) Function overloading has no benefits
Answer: c) Function overloading makes a program easier to read and maintain

65. What happens when an overloaded function is called with different argument types?

a) The compiler selects the best match
b) It causes a runtime error
c) It causes a syntax error
d) It results in undefined behavior
Answer: a) The compiler selects the best match

66. What is method overriding in C++?

a) Declaring a function with the same name in the same class
b) Declaring a function in a derived class that has the same signature as in the base class
c) Declaring multiple functions with the same name in the same scope
d) Using different return types for overloaded functions
Answer: b) Declaring a function in a derived class that has the same signature as in the base class

67. When does method overriding occur?

a) When a derived class redefines a base class function with the same signature
b) When two functions have the same name but different parameters
c) When a function is redefined in the same class
d) When a function is declared static
Answer: a) When a derived class redefines a base class function with the same signature

68. Which keyword is used to prevent a method from being overridden in C++?

a) override
b) static
c) final
d) const
Answer: c) final

69. Which access specifier is required for a base class function to be overridden in a derived class?

a) private
b) public or protected
c) static
d) global
Answer: b) public or protected

70. Can a derived class override a private method of the base class?

a) Yes, always
b) No, because private methods are not accessible to derived classes
c) Yes, but only if the derived class is in the same namespace
d) Yes, if the derived class uses the friend keyword
Answer: b) No, because private methods are not accessible to derived classes

71. What happens if a function in a derived class has the same name as in the base class but with different parameters?

a) It overrides the base class function
b) It overloads the base class function instead of overriding
c) It generates a compilation error
d) It hides the base class function
Answer: b) It overloads the base class function instead of overriding

72. What is the role of the `virtual` keyword in method overriding?

a) It allows a method to be overridden in the derived class
b) It prevents a method from being overridden
c) It makes a method static
d) It forces early binding
Answer: a) It allows a method to be overridden in the derived class

73. What happens if a base class function is not declared as virtual but is overridden in a derived class?

a) Runtime polymorphism is achieved
b) The base class function is hidden but not overridden
c) A compilation error occurs
d) The derived class function cannot be called
Answer: b) The base class function is hidden but not overridden

74. What is the correct way to override a function in C++?

a) By using the virtual keyword in the base class function declaration
b) By using the override keyword in the derived class
c) By using the static keyword in the derived class
d) By using the final keyword in the base class
Answer: a) By using the virtual keyword in the base class function declaration

75. What is the purpose of the `override` keyword in C++11?

a) It forces a function to be overridden in the derived class
b) It explicitly marks a function as overriding a base class function
c) It prevents method overriding
d) It is used to call a function from the base class
Answer: b) It explicitly marks a function as overriding a base class function

76. Which of the following is NOT true about method overriding?

a) Overriding occurs in inheritance
b) The base class function should be virtual
c) The derived class function should have a different name
d) The function signatures must be the same
Answer: c) The derived class function should have a different name

77. How can you call an overridden method of the base class from the derived class?

a) Using super keyword
b) Using base keyword
c) Using BaseClass::methodName()
d) Using override keyword
Answer: c) Using BaseClass::methodName()

78. What is the output of the following code?

#include <iostream>
using namespace std;
class Base {
public:
    virtual void show() { cout << "Base Class" << endl; }
};
class Derived : public Base {
public:
    void show() override { cout << "Derived Class" << endl; }
};
int main() {
    Base* b = new Derived();
    b->show();
    return 0;
}

a) Base Class
b) Derived Class
c) Compilation error
d) Runtime error
Answer: b) Derived Class

79. What will happen if a base class function is declared `virtual` but is not overridden in the derived class?

a) The base class function will be called
b) A compilation error occurs
c) The derived class will generate an exception
d) The function cannot be accessed
Answer: a) The base class function will be called

80. Can a constructor be overridden in C++?

a) Yes
b) No
Answer: b) No

81. What happens if a derived class function has a different return type than the base class function?

a) It overrides the base class function
b) It results in a compilation error
c) It creates an overloaded function
d) It hides the base class function
Answer: b) It results in a compilation error

82. What happens when a function is overridden but the base class function is not virtual?

a) The base class function will be hidden
b) The base class function will be overridden
c) A runtime error occurs
d) The derived class function will not be called
Answer: a) The base class function will be hidden

83. Which of the following can be overridden?

a) Static functions
b) Virtual functions
c) Constructors
d) Private functions
Answer: b) Virtual functions

84. What is pure virtual function in C++?

a) A function that has no implementation and must be overridden in derived classes
b) A function that is only accessible in the base class
c) A function that cannot be inherited
d) A function that is not allowed in a base class
Answer: a) A function that has no implementation and must be overridden in derived classes

85. How can you prevent a function from being overridden in C++?

a) By declaring it as private
b) By using final keyword
c) By declaring it as static
d) By using override keyword
Answer: b) By using final keyword

86. What is run-time polymorphism in C++?

a) Function overloading
b) Operator overloading
c) Method overriding using virtual functions
d) Inline functions
Answer: c) Method overriding using virtual functions

87. Which of the following concepts allows run-time polymorphism in C++?

a) Function overloading
b) Virtual functions
c) Friend functions
d) Static functions
Answer: b) Virtual functions

88. Which of the following keywords is required to achieve run-time polymorphism?

a) static
b) final
c) virtual
d) const
Answer: c) virtual

89. Which of the following statements is true about run-time polymorphism?

a) It is achieved using function overloading
b) It is resolved at compile-time
c) It is achieved using virtual functions and function overriding
d) It does not use pointers
Answer: c) It is achieved using virtual functions and function overriding

90. What is required for a function to support run-time polymorphism?

a) It must be a global function
b) It must be a static function
c) It must be declared virtual in the base class
d) It must be declared as inline
Answer: c) It must be declared virtual in the base class

91. When is the function that is overridden in a derived class executed?

a) At compile-time
b) At run-time
c) At link-time
d) At design-time
Answer: b) At run-time

92. What does the following code print?

#include <iostream>
using namespace std;
class Base {
public:
    virtual void show() { cout << "Base class" << endl; }
};
class Derived : public Base {
public:
    void show() override { cout << "Derived class" << endl; }
};
int main() {
    Base* b = new Derived();
    b->show();
    return 0;
}

a) Base class
b) Derived class
c) Compilation error
d) Runtime error
Answer: b) Derived class

93. How is run-time polymorphism achieved in C++?

a) Function overloading
b) Operator overloading
c) Virtual functions and pointers
d) Friend functions
Answer: c) Virtual functions and pointers

94. What is the output of the following code?

#include <iostream>
using namespace std;
class A {
public:
    virtual void display() { cout << "A"; }
};
class B : public A {
public:
    void display() { cout << "B"; }
};
int main() {
    A* obj = new B();
    obj->display();
    return 0;
}

a) A
b) B
c) Compilation error
d) Runtime error
Answer: b) B

95. What is dynamic binding in C++?

a) Binding function calls at compile-time
b) Binding function calls at run-time
c) Using const keyword to prevent changes
d) Using friend functions
Answer: b) Binding function calls at run-time

96. Which function type does NOT support run-time polymorphism?

a) Virtual functions
b) Static functions
c) Overridden functions
d) Base class functions
Answer: b) Static functions

97. Can a static function be virtual in C++?

a) Yes
b) No
Answer: b) No

98. How does C++ determine which function to execute in run-time polymorphism?

a) Using function overloading
b) Using early binding
c) Using vtable (virtual table) mechanism
d) Using default arguments
Answer: c) Using vtable (virtual table) mechanism

99. Which of the following is NOT necessary for run-time polymorphism?

a) Virtual function in base class
b) Function with same signature in derived class
c) Object slicing
d) Base class pointer or reference
Answer: c) Object slicing

100. What happens when a virtual function is not overridden in the derived class?

a) The base class function is called
b) A compilation error occurs
c) A runtime error occurs
d) The function cannot be accessed
Answer: a) The base class function is called

101. What is a pure virtual function?

a) A function with no implementation in the base class
b) A function that is overridden in the same class
c) A function that cannot be inherited
d) A function that cannot be overridden
Answer: a) A function with no implementation in the base class

102. What is the syntax of a pure virtual function?

a) virtual void show();
b) virtual void show() = 0;
c) void show() = 0;
d) void virtual show() {}
Answer: b) virtual void show() = 0;

103. Which of the following statements is true?

a) Virtual functions can be called using object names
b) Virtual functions are used for early binding
c) Virtual functions allow dynamic method dispatch
d) Virtual functions cannot be overridden
Answer: c) Virtual functions allow dynamic method dispatch

104. What will happen if a pure virtual function is not implemented in a derived class?

a) The derived class becomes an abstract class
b) The base class function is called
c) A runtime error occurs
d) Compilation fails
Answer: a) The derived class becomes an abstract class

105. What is the default return type of a virtual function?

a) void
b) int
c) Same as the overridden function
d) No default type
Answer: c) Same as the overridden function

106. Can a destructor be virtual?

a) Yes
b) No
Answer: a) Yes

107. What will happen if a base class destructor is not virtual?

a) Memory leaks may occur
b) The derived class destructor is called first
c) The base class destructor is called first
d) The program crashes
Answer: a) Memory leaks may occur

108. What is the vtable in C++?

a) A table storing virtual functions of a class
b) A table storing function overloading information
c) A table storing constructor definitions
d) A table storing friend functions
Answer: a) A table storing virtual functions of a class

109. How can you prevent a class from being inherited in C++?

a) By declaring it private
b) By using final keyword
c) By using static keyword
d) By using virtual keyword
Answer: b) By using final keyword

110. What is function overriding?

a) Defining multiple functions with the same name in the same scope
b) Redefining a base class function in a derived class with the same signature
c) Using a function with different parameter types
d) Using a function with different return types
Answer: b) Redefining a base class function in a derived class with the same signature

111. What is multiple inheritance in C++?

a) A class inheriting from multiple base classes
b) A class inheriting from a single base class
c) A function overloading mechanism
d) A template class inheritance
Answer: a) A class inheriting from multiple base classes

112. How do you declare multiple inheritance in C++?

a) class Derived : public Base1, Base2
b) class Derived : Base1, public Base2
c) class Derived : public Base1, public Base2
d) class Derived (Base1, Base2)
Answer: c) class Derived : public Base1, public Base2

113. What is the main drawback of multiple inheritance?

a) It increases code reusability
b) It increases the execution speed
c) It can lead to the diamond problem
d) It makes class structure simpler
Answer: c) It can lead to the diamond problem

114. Which keyword helps solve the diamond problem in multiple inheritance?

a) virtual
b) static
c) protected
d) friend
Answer: a) virtual

115. In multiple inheritance, which constructor is executed first?

a) Derived class constructor
b) The constructor of the first base class specified
c) The constructor of the last base class specified
d) The constructor of the derived class only
Answer: b) The constructor of the first base class specified

116. What happens when a function with the same name exists in both base classes?

a) Compilation error
b) Ambiguity error unless resolved in the derived class
c) The function in the first base class is called
d) The function in the last base class is called
Answer: b) Ambiguity error unless resolved in the derived class

117. How can function ambiguity be resolved in multiple inheritance?

a) By using scope resolution operator (::)
b) By using friend functions
c) By declaring the function static
d) By overloading the function
Answer: a) By using scope resolution operator (::)

118. What is the correct way to call a function from a specific base class?

Derived obj;
obj.function();

a) obj.function();
b) Base1::function();
c) obj.Base1::function();
d) Base1 obj.function();
Answer: c) obj.Base1::function();

119. What is the syntax to declare a virtual base class in C++?

a) class A : virtual B
b) class A : public virtual B
c) class A { virtual B; }
d) class A : B virtual
Answer: b) class A : public virtual B

120. What is the role of a virtual base class?

a) To allow the derived class to access private members of the base class
b) To allow multiple instances of the base class in the inheritance hierarchy
c) To prevent multiple copies of the base class in the derived class
d) To prevent function overriding
Answer: c) To prevent multiple copies of the base class in the derived class

121. What will happen if the diamond problem is not handled properly?

a) Compilation error
b) Ambiguous base class reference
c) Function overloading error
d) Infinite loop
Answer: b) Ambiguous base class reference

122. Which of the following is true about multiple inheritance?

a) It always leads to the diamond problem
b) It cannot be used in C++
c) It allows a derived class to inherit from multiple base classes
d) It requires all functions to be virtual
Answer: c) It allows a derived class to inherit from multiple base classes

123. How does C++ handle multiple inheritance internally?

a) Using vtable and vptr
b) Using inline expansion
c) Using function overloading
d) Using preprocessor macros
Answer: a) Using vtable and vptr

124. Can a derived class have multiple virtual base classes?

a) Yes
b) No
Answer: a) Yes

125. What is the output of the following code?

#include <iostream>
using namespace std;
class A { public: void show() { cout << "A"; } };
class B { public: void show() { cout << "B"; } };
class C : public A, public B {};
int main() {
    C obj;
    obj.show();
    return 0;
}

a) A
b) B
c) Compilation error
d) Runtime error
Answer: c) Compilation error (Ambiguity error)

126. How do you resolve ambiguity in multiple inheritance?

a) Using scope resolution operator
b) Using static functions
c) Using friend functions
d) Using private access specifier
Answer: a) Using scope resolution operator

127. What happens if a derived class does not override a virtual function from multiple base classes?

a) The base class function with the highest priority is called
b) The function from the first base class is called
c) The function from the last base class is called
d) Ambiguity error
Answer: d) Ambiguity error

128. Can a destructor be virtual in multiple inheritance?

a) Yes
b) No
Answer: a) Yes

129. Which of the following is a valid example of multiple inheritance?

a) class A : public B, public C {}
b) class A { class B, class C };
c) class A, B : public C {};
d) class A { public: B, public: C };
Answer: a) class A : public B, public C {}

130. What is the output of the following code?

#include <iostream>
using namespace std;
class A { public: virtual void show() { cout << "A"; } };
class B : public virtual A { public: void show() { cout << "B"; } };
class C : public virtual A { public: void show() { cout << "C"; } };
class D : public B, public C {};
int main() {
    D obj;
    obj.show();
    return 0;
}

a) A
b) B
c) C
d) Compilation error
Answer: c) C (Method resolution follows the rightmost base class)

131. What is hybrid inheritance?

a) A mix of multiple and single inheritance
b) Inheriting multiple base classes and a single derived class
c) Overloading operators in multiple classes
d) Using friend functions to access private members
Answer: a) A mix of multiple and single inheritance

132. In multiple inheritance, which constructor is called first?

a) Derived class constructor
b) First base class constructor
c) Last base class constructor
d) None
Answer: b) First base class constructor

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BCA 2nd Sem -Object Oriented Programming Using C++ UNIT-IV MCQ

Object Oriented Programming Using C++

1. What is a template function in C++?

a) A function that can accept only integer arguments b) A function that can work with different data types c) A function that cannot return any value d) A function with a fixed return type Answer: b) A function that can work with different data types

2. Which keyword is used to define a template function in C++?

a) template b) generic c) typename d) class Answer: a) template

3. What is the correct syntax for defining a function template?

a) template <typename T> T func(T a, T b); b) generic <class T> T func(T a, T b); c) class <typename T> T func(T a, T b); d) template generic <T> T func(T a, T b); Answer: a) template <typename T> T func(T a, T b);

4. What is the primary purpose of function templates?

a) To write multiple functions with different names b) To allow a single function to handle multiple data types c) To improve memory allocation d) To replace pointers in C++ Answer: b) To allow a single function to handle multiple data types

5. How do we define multiple template parameters in a function template?

a) template <class T, class U> b) template (class T, class U) c) template {class T, class U} d) template [class T, class U] Answer: a) template <class T, class U>

6. What is the difference between typename and class in templates?

7. Which of the following is TRUE about function templates?

a) Function templates must have at least one parameter b) Function templates can only return void c) Function templates allow writing generic code for multiple types d) Function templates cannot be overloaded Answer: c) Function templates allow writing generic code for multiple types

8. How is a function template instantiated?

a) Automatically when it is called with a specific data type b) Manually using the new keyword c) By defining it inside a class d) Using the class keyword Answer: a) Automatically when it is called with a specific data type

9. What happens if a function template is called with a data type that it does not support?

a) The compiler generates an error b) The function executes with a default type c) The program crashes at runtime d) The function ignores the unsupported data type Answer: a) The compiler generates an error

10. Can function templates be overloaded?

a) No, function templates cannot be overloaded b) Yes, but only with non-template functions c) Yes, function templates can be overloaded d) Only in C++17 and later versions Answer: c) Yes, function templates can be overloaded

11. What is the correct way to call a function template explicitly?

a) func<int>(10, 20); b) func<int, 10, 20>; c) func(10, 20) <int>; d) func<int> {10, 20}; Answer: a) func<int>(10, 20);

12. What is a non-type template parameter?

13. Can function templates return a value?

a) Yes, they can return any data type b) No, they always return void c) Yes, but only integer values d) Only if they use static keyword Answer: a) Yes, they can return any data type

14. What is template specialization?

15. Can a function template have a default parameter?

a) Yes, it can have default parameters b) No, default parameters are not allowed in templates c) Only if the function is inline d) Only if it is a non-member function Answer: a) Yes, it can have default parameters

16. What is the correct way to define a function template for swapping two values?

a) template <typename T> void swapValues(T &a, T &b) { T temp = a; a = b; b = temp; } b) void swapValues(T a, T b) { T temp = a; a = b; b = temp; } c) template swapValues(T a, T b) { T temp = a; a = b; b = temp; } d) class T swapValues(T a, T b) { T temp = a; a = b; b = temp; } Answer: a)

17. What is function template instantiation?

a) Creating a specific version of the template function for a given data type b) Deleting a function template from memory c) Overloading a function template d) Using a function template inside a class Answer: a) Creating a specific version of the template function for a given data type

18. Can a function template have multiple parameters of different types?

a) Yes b) No Answer: a) Yes

19. What is the advantage of using function templates?

a) Reduces code duplication b) Increases memory usage c) Slows down program execution d) Complicates debugging Answer: a) Reduces code duplication

20. What happens if a function template is not used in a program?

a) The compiler does not generate any code for it b) The compiler generates a warning c) The program crashes d) The function template gets deleted automatically Answer: a) The compiler does not generate any code for it

21. Which of the following statements is true about function templates?

a) They can only be defined in the main() function. b) They can have multiple template parameters. c) They cannot be overloaded. d) They must always return void. Answer: b) They can have multiple template parameters.

22. What happens if a function template is defined but never used in a program?

a) The compiler will generate an error. b) The function will still be compiled and added to the executable. c) The function template will not be instantiated. d) The linker will remove it during optimization. Answer: c) The function template will not be instantiated.

23. What is the correct syntax for using a template function explicitly for double type?

a) func<double>(10.5, 20.5); b) func(10.5, 20.5)<double>; c) func<double>{10.5, 20.5}; d) func(double 10.5, double 20.5); Answer: a) func<double>(10.5, 20.5);

24. Can a function template accept both template and non-template parameters?

a) Yes b) No Answer: a) Yes

25. What does the following function template do?

template <typename T>T square(T x) { return x * x; } a) Squares the given value of any data type b) Returns the square root of the input c) Multiplies x by itself only if x is an integer d) Causes a compilation error Answer: a) Squares the given value of any data type

26. Which of the following is true about function templates?

a) They reduce code duplication. b) They increase compilation time. c) They cannot be used for user-defined types. d) They require explicit specialization for all types. Answer: a) They reduce code duplication.

27. Can function templates be used with user-defined types like struct or class?

a) Yes b) No Answer: a) Yes

28. What is an explicit specialization of a function template?

a) Providing a specific implementation for a certain data type. b) Using explicit keyword inside a template function. c) Making a function template private. d) Preventing a function template from being instantiated. Answer: a) Providing a specific implementation for a certain data type.

29. What is an advantage of using function templates?

a) They allow generic programming. b) They eliminate the need for function overloading. c) They improve code reusability. d) All of the above. Answer: d) All of the above.

30. What does this code do?

template <class T>T add(T a, T b) { return a + b; } int main() { cout << add(10, 20) << endl; } a) Prints 30 b) Causes a runtime error c) Prints 1020 d) Causes a compilation error Answer: a) Prints 30

31. What happens when a function template is instantiated with different data types?

a) The compiler generates a separate function for each type. b) The same function instance is used for all data types. c) The template cannot be instantiated with different types. d) It results in an error. Answer: a) The compiler generates a separate function for each type.

32. What is function template overloading?

a) Defining multiple function templates with different parameter lists. b) Using multiple templates inside a single function. c) Calling a function template multiple times. d) Using #define macros instead of templates. Answer: a) Defining multiple function templates with different parameter lists.

33. What is the main difference between function overloading and function templates?

34. Which of the following can be a non-type template parameter?

a) int b) char c) bool d) All of the above Answer: d) All of the above

35. Which of the following is an invalid function template declaration?

a) template <class T> T func(T a, T b); b) template <typename T> void print(T a); c) template (class T) T sum(T a, T b); d) template <class T, class U> T add(T a, U b); Answer: c) template (class T) T sum(T a, T b);

36. Can we create a template function inside a class?

a) Yes b) No Answer: a) Yes

37. How can we restrict a function template to work with only integer types?

a) Using enable_if or explicit specialization b) Using the restrict keyword c) It is not possible d) Using const keyword Answer: a) Using enable_if or explicit specialization

38. Can function templates be recursive?

a) Yes b) No Answer: a) Yes

39. What happens if a function template has a static variable?

a) Each instantiation gets its own copy of the variable. b) The same static variable is shared among all instances. c) The function cannot be instantiated. d) Causes a compilation error. Answer: a) Each instantiation gets its own copy of the variable.

40. What is a variadic template function?

41. What is function overloading in C++?

42. What must be different in overloaded functions?

a) A function that can accept only integer arguments
b) A function that can work with different data types
c) A function that cannot return any value
d) A function with a fixed return type
Answer: b) A function that can work with different data types

a) `template`
b) `generic`
c) `typename`
d) `class`
Answer: a) `template`

a) `template <typename T> T func(T a, T b);`
b) `generic <class T> T func(T a, T b);`
c) `class <typename T> T func(T a, T b);`
d) `template generic <T> T func(T a, T b);`
Answer: a) `template <typename T> T func(T a, T b);`

a) To write multiple functions with different names
b) To allow a single function to handle multiple data types
c) To improve memory allocation
d) To replace pointers in C++
Answer: b) To allow a single function to handle multiple data types

a) `template <class T, class U>`
b) `template (class T, class U)`
c) `template {class T, class U}`
d) `template [class T, class U]`
Answer: a) `template <class T, class U>`

6. What is the difference between `typename` and `class` in templates?

a) Function templates must have at least one parameter
b) Function templates can only return `void`
c) Function templates allow writing generic code for multiple types
d) Function templates cannot be overloaded
Answer: c) Function templates allow writing generic code for multiple types

a) Automatically when it is called with a specific data type
b) Manually using the `new` keyword
c) By defining it inside a class
d) Using the `class` keyword
Answer: a) Automatically when it is called with a specific data type

a) The compiler generates an error
b) The function executes with a default type
c) The program crashes at runtime
d) The function ignores the unsupported data type
Answer: a) The compiler generates an error

a) No, function templates cannot be overloaded
b) Yes, but only with non-template functions
c) Yes, function templates can be overloaded
d) Only in C++17 and later versions
Answer: c) Yes, function templates can be overloaded

a) `func<int>(10, 20);`
b) `func<int, 10, 20>;`
c) `func(10, 20) <int>;`
d) `func<int> {10, 20};`
Answer: a) `func<int>(10, 20);`

a) Yes, they can return any data type
b) No, they always return `void`
c) Yes, but only integer values
d) Only if they use `static` keyword
Answer: a) Yes, they can return any data type

a) Yes, it can have default parameters
b) No, default parameters are not allowed in templates
c) Only if the function is inline
d) Only if it is a non-member function
Answer: a) Yes, it can have default parameters

a) Creating a specific version of the template function for a given data type
b) Deleting a function template from memory
c) Overloading a function template
d) Using a function template inside a class
Answer: a) Creating a specific version of the template function for a given data type

a) Yes
b) No
Answer: a) Yes

a) Reduces code duplication
b) Increases memory usage
c) Slows down program execution
d) Complicates debugging
Answer: a) Reduces code duplication

a) The compiler does not generate any code for it
b) The compiler generates a warning
c) The program crashes
d) The function template gets deleted automatically
Answer: a) The compiler does not generate any code for it

a) They can only be defined in the `main()` function.
b) They can have multiple template parameters.
c) They cannot be overloaded.
d) They must always return `void`.
Answer: b) They can have multiple template parameters.

a) The compiler will generate an error.
b) The function will still be compiled and added to the executable.
c) The function template will not be instantiated.
d) The linker will remove it during optimization.
Answer: c) The function template will not be instantiated.

23. What is the correct syntax for using a template function explicitly for `double` type?

a) `func<double>(10.5, 20.5);`
b) `func(10.5, 20.5)<double>;`
c) `func<double>{10.5, 20.5};`
d) `func(double 10.5, double 20.5);`
Answer: a) `func<double>(10.5, 20.5);`

a) Yes
b) No
Answer: a) Yes

template <typename T>
`T square(T x) { return x * x; }`
a) Squares the given value of any data type
b) Returns the square root of the input
c) Multiplies `x` by itself only if `x` is an integer
d) Causes a compilation error
Answer: a) Squares the given value of any data type

a) They reduce code duplication.
b) They increase compilation time.
c) They cannot be used for user-defined types.
d) They require explicit specialization for all types.
Answer: a) They reduce code duplication.

27. Can function templates be used with user-defined types like `struct` or `class`?

a) Yes
b) No
Answer: a) Yes

a) Providing a specific implementation for a certain data type.
b) Using `explicit` keyword inside a template function.
c) Making a function template `private`.
d) Preventing a function template from being instantiated.
Answer: a) Providing a specific implementation for a certain data type.

a) They allow generic programming.
b) They eliminate the need for function overloading.
c) They improve code reusability.
d) All of the above.
Answer: d) All of the above.

template <class T>
`T add(T a, T b) { return a + b; } int main() { cout << add(10, 20) << endl; }`
a) Prints `30`
b) Causes a runtime error
c) Prints `1020`
d) Causes a compilation error
Answer: a) Prints `30`

a) The compiler generates a separate function for each type.
b) The same function instance is used for all data types.
c) The template cannot be instantiated with different types.
d) It results in an error.
Answer: a) The compiler generates a separate function for each type.

a) `int`
b) `char`
c) `bool`
d) All of the above
Answer: d) All of the above

a) `template <class T> T func(T a, T b);`
b) `template <typename T> void print(T a);`
c) `template (class T) T sum(T a, T b);`
d) `template <class T, class U> T add(T a, U b);`
Answer: c) `template (class T) T sum(T a, T b);`

a) Yes
b) No
Answer: a) Yes

a) Using `enable_if` or explicit specialization
b) Using the `restrict` keyword
c) It is not possible
d) Using `const` keyword
Answer: a) Using `enable_if` or explicit specialization

a) Yes
b) No
Answer: a) Yes

a) Each instantiation gets its own copy of the variable.
b) The same static variable is shared among all instances.
c) The function cannot be instantiated.
d) Causes a compilation error.
Answer: a) Each instantiation gets its own copy of the variable.

72. What is the role of the `virtual` keyword in method overriding?

75. What is the purpose of the `override` keyword in C++11?

79. What will happen if a base class function is declared `virtual` but is not overridden in the derived class?