Object Oriented MCQ Set 1
1. What are local classes?
a) Classes declared inside a package
b) Classes declared inside a function
c) Classes declared inside a class
d) Classes declared inside structure
Answer
Answer: b [Reason:] The classes declared inside a package are available to all the functions and classes, hence can’t be called local. This is somewhat similar concept that we use to denote variables of a function. The classes declared inside functions will be local to them.
2. All member functions of a local class must be _____
a) Defined outside class body
b) Defined outside the function definition
c) Defined inside the class body
d) Defined at starting of program
Answer
Answer: c [Reason:] There is a restriction on where the member functions of the local class should be define. Those must be defined inside the class body only. This is to reduce the ambiguity and complexity of program.
3. Can local class members access/use the general local variables (except static, abstract etc.) of the function in which it is defined?
a) Yes, it can access with arrow operator
b) No, it can’t access with dot operator
c) Yes, it can access using dot operator
d) No, it can’t access In anyway
Answer
Answer: d [Reason:] The local variables of the functions are not available to the member functions of the class. This is done to reduce the ambiguity in variables and their access rules.
4. Which type of data can a local class access from the function in which it is defined?
a) Static and extern
b) Abstract and static
c) Void and extern
d) Const and static
Answer
Answer: a [Reason:] The local classes have this feature to access the static and extern variables of the function in which those are defined. This feature is available since these type of data are common to the program and is created only one time. Run time creation and destruction of these variables is not done. The only restriction that may apply is those members must be constants.
5. Local classes can access the type names and enumerators defined by the enclosing function.
a) True
b) False
Answer
Answer: a [Reason:] This is a little tricky part with local classes. Though the local class can’t access the general variables of the function but can access the types that are defined inside the function. This is because the whole definition of that type would be existing inside the class.
6. Can static variables be declared inside a local class?
a) Yes, with public access specifier
b) Yes, anywhere as required
c) No, not possible in private access specifier
d) No, not possible anyway
Answer
Answer: d [Reason:] No, the static variables can’t be declared inside a local class. This is because each time the function is called, all the variables get created again and are destroyed as soon as the function is returned. This would have been possible id the static variable was of function.
7. All the member functions of local classes are ____ by default.
a) Static
b) Inline
c) Abstract
d) Virtual
Answer
Answer: c [Reason:] All the members are defined inside the class body. And when the member functions are defined inside the class body, they are made inline by default. If the definition is too complex, those are made normal functions.
8. The enclosing function has no special access to the members of local class. (True/False)
a) True
b) False
Answer
Answer: a [Reason:] This is a rule that the enclosing function doesn’t have any special access to the members of local class. This is done to maintain the security of class members. And to adhere to the rules of OOP.
9. Which language can use inheritance with local classes?
a) Kotlin
b) Java
c) SmallTalk
d) SAP ABAP
Answer
Answer: d [Reason:] Other language might support inheritance with local classes but those doesn’t provide all the proper features of inheritance. Language SAP ABAP provides a way to implement inheritance with local classes efficiently.
10. How many local classes can be defined inside a single function?
a) Only 1
b) Only 3
c) Only 5
d) As many as required
Answer
Answer: d [Reason:] The local classes can be defined as required. There is no restriction on the number of local classes that can be defined inside a function. But all those classes must follow the rules and restrictions.
11. All the data members of local class must be _____
a) Defined with declaration
b) Defined in constructor
c) Declared and defined in constructor
d) Declared using a member function
Answer
Answer: b [Reason:] The data members follow same rules as of simple classes. Hence the data members must be declared first. Then their definition must be given using the constructors.
12. Can two different functions have local class with same name?
a) Yes, since local
b) No, names must be different
c) No, scope doesn’t work here
d) No, ambiguity arises
Answer
Answer: a [Reason:] The local classes can have same name if they belong to different functions. The classes would be local to those specific functions and hence can have same name. This is same as that of local variables concept.
13. What is the scope of local class?
a) Within the class only
b) Within the function
c) Within the program
d) One time creation and live till end of program
Answer
Answer: b [Reason:] The scope of a local class is limited only within the function definition. The function can use the class as usual as local variables. The class gets destroyed as soon as the function is returned.
14. Can a function, other than the enclosing function of local class, access the class members?
a) Yes, using object
b) Yes, using direct call
c) Yes, using pointer
d) No, can’t access
Answer
Answer: d [Reason:] The local classes are local to the specific enclosing function. Other functions can’t access the class. Even if the pointers are used, the class must be alive when the pointer is used. But this will not happen if the enclosing function is returned.
15. Which among the following is main advantage of using local classes?
a) Make program more efficient
b) Makes program execution faster
c) Helps to add extra functionality to a function
d) Helps to add more members to a function
Answer
Answer: c [Reason:] The closest answer is to add more functionalities to a function or to make some specific functions to be generic. Adding more members to a function can be done directly but to add some special functionality that are encapsulated, can be done using local classes.
Object Oriented MCQ Set 2
1. Which among the following is main use of object?
a) To create instance of a function
b) To create instance of a program
c) To create instance of class
d) To create instance of structures
Answer
Answer: c [Reason:] The objects are used to create instance of a class. Objects can represent a class in an independent form. The basic blueprint, that contains the information of the type of data that can be stored in an object, is given by the class.
2. Which among the following is not a property of an object?
a) Identity
b) Properties
c) Attributes
d) Names
Answer
Answer: d [Reason:] The names are not property of an object. The identity can be in any form like address or name of object but name can’t be termed as only identity of an object. The objects contain attributes that define what type of data an object can store.
3. What is function object?
a) An object with a single function
b) An object with only functions
c) An object with more than one function
d) An object with no functions
Answer
Answer: a [Reason:] A function object is the object with single function. In C++ a function object can be like operator() function. This acts more like a function rather than an object.
4. Immutable object are used ______
a) To set up as a fixed state
b) To set up variable object
c) To set up an object of abstract class
d) To set up an object of derived class
Answer
Answer: a [Reason:] An immutable object can be created for an object which have to be fixed with values. The object data will not be changed throughout the program. This can be useful to eliminate the unintentional changes in the data of object.
5. Which object can be used to contain other objects?
a) First class object
b) Derived class object
c) Container object
d) Enclosure object
Answer
Answer: c [Reason:] A container object can be used to contain other objects. Container object is an ADT. Its object are collection of other objects. Some specific rules apply to these type of objects.
6. A factory object is used ______
a) To create new classes
b) To create new function
c) To create new data members
d) To create new objects
Answer
Answer:d [Reason:] The factory object is an object that can be used to create other objects. If it is seen formally, it behaves like a method that will return object on its use. The object returned is assumed to be a new object.
7. What are singleton objects?
a) The only two objects of a class throughout the program
b) The only object of a class throughout the program
c) The objects that are alive throughout the program
d) The objects that are created and then deleted without use
Answer
Answer: b [Reason:] If a class has only one object created and that is the only object of the class. Then the object is known as singleton object. But only if that object is the only object of the class and no other object is created for that class.
8. Object cout and cin _____
a) Can be used directly with << and >> symbols respectively
b) Can be used directly with >> and << symbols respectively
c) Must be used as a function which accepts 2 arguments
d) Must be used as a function which accepts 3 arguments
Answer
Answer: a [Reason:] The cin and cout objects can be used directly with the >> and << operators respectively. The objects are of iostream class. Class iostream is an inbuilt class.
9. Objects type ____
a) Can be changed in runtime
b) Can’t be changed in runtime
c) Can be changed in compile time
d) May or may not get changed
Answer
Answer: b [Reason:] The object types are always fixed. Once the object is created of a specific type then it can’t be changed. Neither at runtime nor at compile time.
10. An object can be used to represent _____
a) A real world entity
b) A real function
c) Some real data only
d) Some function only
Answer
Answer: a [Reason:] The objects are actually meant to represent an entity. The classes are real world object’s blue print. The classes then are used to create an entity representation.
11. Objects can be used _____
a) To access any member of a class
b) To access only pubic members of a class
c) To access only protected members of a class
d) To access only private members of a class
Answer
Answer: b [Reason:] The objects are created for a specific class. Then the objects can be used to access the public members of a class. The members can be the data members or the member functions of the class.
12. Which among the following is not a use of object?
a) Defining a member function
b) Accessing data members
c) Creating instance of a class
d) Using class members
Answer
Answer: a [Reason:] The objects can’t be used to define any member function. Member functions must be defined by the class only. Objects can only access the members and use them.
13. Which object can be used to access the standard input?
a) System.inner
b) cin
c) System.stdin
d) console.input
Answer
Answer: b [Reason:] Object cin can be used to take input from the standard input. It is used in C++. In java we can use System.in for the standard input stream. The syntax changes from language to language.
14. A single object can be used ______
a) As only two class types at a time
b) As only three class types at a time
c) As only one class type at a time
d) As of as many class types as required
Answer
Answer: c [Reason:] The object can be of only one type. The type of an object can’t be changed. Object type is mandatory to be of one class type to ensure the type and number of data members it have.
15. If same object name is given to different objects of different class then _______
a) Its compile time error
b) Its runtime error
c) It’s not an error
d) Program suns smooth
Answer
Answer: a [Reason:] It is a compile time error as the compiler doesn’t allow same name objects to be declared more than once. Compiler produces multiple declaration error. Every object must have a different name.
Object Oriented MCQ Set 3
1. Which among the following best describes member functions?
a) Functions which are defined within the class
b) Functions belonging a class
c) Functions in public access of a class
d) Functions which are private to class
Answer
Answer: b [Reason:] We can’t say that only functions which are defined inside class are member functions. There can be some inherited functions. Though they doesn’t belong to the class but are property of the objects once inheritance is used. So the nearest definition is functions belonging a class.
2. How many types of member functions are generally there in C++?
a) 2
b) 3
c) 4
d) 5
Answer
Answer: d [Reason:] There are 5 types of member functions that are generally provided in C++. Namely, simple, static, const, inline and friend member functions. Member functions are specific to classes.
3. How can a static member function be called in main function?
a) Using dot operator
b) Using arrow operator
c) Using dot or arrow operator
d) Using dot, arrow or using scope resolution operator with class name
Answer
Answer: d [Reason:] The member functions can be called using only the dot operator or the arrow operator. But the static members can be called using directly the class name followed by the scope resolution operator and static member function name. This is useful when you don’t have any object to call the member.
4. What are inline member funcitons?
a) Member functions which can be called without object
b) Member functions whose definition is expanded in place of its call
c) Member functions whose definition is faster than simple function
d) Member function which is defined in single line
Answer
Answer: b [Reason:] The member functions whose definition is expanded at the call, and no jump to function and return happened, are termed as inline functions. This is used to make the program faster and more efficient.
5. What happens if non static members are used in static member function?
a) Compile time error
b) Runtime error
c) Executes fine
d) Executes if that member function is not used
Answer
Answer: a [Reason:] There must be specific memory space allocated for the data members before the static member functions uses them. But the space is not reserved if object is not declared. Hence only if static members are not used, it leads to compile time error.
6. Static member functions _______
a) Contains “this” pointer for data members
b) Contains “this” pointer if used for member functions
c) Doesn’t contain “this” pointer
d) Doesn’t contain “this” pointer if member functions are referred
Answer
Answer: c [Reason:] The static member functions doesn’t contain “this” pointer. Static member functions can’t be defined as const or volatile also. These are restrictions on static member functions.
7. How to access members of the class inside a member function?
a) Using this pointer only
b) Using dot operator
c) Using arrow operator
d) Used directly or with this pointer
Answer
Answer: d [Reason:] The members of a class can be used directly inside a member function. We can use this pointer when there is a conflict between data members of class and arguments/local function variable names.
8. For overloading “( )”, “[ ]” or “->” operators, a class ____
a) Must use static member functions
b) Must use non-static member functions
c) Must be non-static member and should not be friend of class
d) Must use static member function or a friend member function
Answer
Answer: c [Reason:] For overloading those operators for a class, the class must use non-static member function so that doesn’t remain common to all the objects, and each object can use it independently. The friend functions is also restricted so as to keep the security of data.
9. If a virtual member function is defined, _____
a) It should not contain any body and defined by subclasses
b) It must contain body and overridden by subclasses
c) It must contain body and be overloaded
d) It must not contain any body and should not be derived
Answer
Answer: a [Reason:] The virtual functions are defined using virtual keyword. These are made in order to make all the classes to define them as the class gets inherited. Increases code understanding.
10. Member functions of a generic class are _______
a) Not generic
b) Automatically generic
c) To be made generic explicitly
d) Given default type as double
Answer
Answer: b [Reason:] When generic type is used in a class, the functions are automatically generic. This is so because the functions would use the same type as defined to make the class generic. The functions will get to know the type of data as soon as the generic class is used. It’s inbuilt feature.
11. Member function of a class can ______
a) Access all the members of the class
b) Access only Public members of the class
c) Access only the private members of the class
d) Access subclass members
Answer
Answer: a [Reason:] The member functions has access to all the members of the class. Whenever data members of a class, which might be private, have to be modified, we make use of these member functions. This is more secure way to manipulate data.
12. Which among the following is proper syntax for class given below?
class A { int a,b; public : void disp(); }
a) void disp::A(){ }
b) void A::disp(){ }
c) void A:disp() { cout<<a<<b ; }
d) void disp:A(){ cout<<a<<b; }
Answer
Answer: b [Reason:] The syntax in option b is correct. We use scope resolution to represent the member function of a class and to write its definition. It is not necessary for a function to have anything in its definition.
13. A member function can ___ of the same class
a) Call other member functions
b) Call only private member functions
c) Call only static member functions
d) Call only const member funcitons
Answer
Answer: a [Reason:] We can call one function inside another function to access some data of class. A public member function can be used to call a private member function which directly manipulates the private data of class.
14. Which member function doesn’t require any return type?
a) Static
b) Constructor
c) Const
d) Constructor and destructor
Answer
Answer: d [Reason:] All the member functions work same as normal functions with syntax. But the constructor and destructor are also considered as member functions of a class, and they never have any data type.
15. Which among the following is not possible for member function?
a) Access protected members of parent class
b) Definition without return type
c) Access public members of subclass
d) Access static members of class
Answer
Answer: c [Reason:] A member function of a class can only have the access to the members of its own class and parent classes if inheritance used. Otherwise a member function can never access the members of a subclass. Accessing static members of a class is possible by normal and static member functions.
Object Oriented MCQ Set 4
1. Which among the following best defines multilevel inheritance?
a) A class derived from another derived class
b) Classes being derived from other derived classes
c) Continuing single level inheritance
d) Class which have more than one parent
Answer
Answer: b [Reason:] Only if the class is being derived from other derived class, it can be called as multilevel inheritance. If a class is derived from another class, it is single level inheritance. There must be more than one level of inheritance.
2. If there are 5 classes, E is derived from D, D from C, C from B and B from A. Which class constructor will be called first if the object of E or D is created?
a) A
b) B
c) C
d) A and B
Answer
Answer: a [Reason:] A is parent of all other classes indirectly. Since A is parent of B and B is parent of C and so on till E. Class A constructor will be called first always.
3. If there are 3 classes. Class C is derived from class B and B is derived from A, Which class destructor will be called at last if object of C is destroyed.
a) A
b) B
c) C
d) All together
Answer
Answer: a [Reason:] The destructors are called in the reverse order of the constructors being called. Hence in multilevel inheritance, the constructors are created from parent to child, which leads to destruction from child to parent. Hence class A destructor will be called at last.
4. Which Class is having highest degree of abstraction in multilevel inheritance of 5 levels?
a) Class at 1st level
b) Class 2nd last level
c) Class at 5th level
d) All with same abstraction
Answer
Answer: a [Reason:] The class with highest degree of abstraction will be the class at the 1st level. You can look at a simple example like, a CAR is more abstract than SPORTS CAR class. The level of abstraction decrease with each level as more details comes out.
5. If all the classes use private inheritance in multilevel inheritance then ________
a) It will not be called multilevel inheritance
b) Each class can access only non-private members of its parent
c) Each subsequent class can access all members of previous level parent classes
d) None of the members will be available to any other class
Answer
Answer: b [Reason:] The classes will be able to access only the non-private members of its parent class. The classes are using private inheritance, hence all the members of parent class become private in the derived class. In turn those won’t be allowed for further inheritance or direct access outside the class.
6. Multilevel inheritance allows _____ in the program.
a) Only 7 levels of inheritance
b) At least 7 levels of inheritance
c) At most 16 levels of inheritance
d) As many levels of inheritance as required
Answer
Answer: d [Reason:] The multilevel inheritance allows any number of levels of inheritance. This is the maximum flexibility feature to make the members available to all the new classes and to add their own functionalities. The code reusability is used too.
7. What is minimum number of levels for a implementing multilevel inheritance?
a) 1
b) 2
c) 3
d) 4
Answer
Answer: c [Reason:] There must be at least 3 levels of inheritance. Otherwise if less, it will be single level inheritance or would have got no inheritance implemented. There must be a derived class from which another class is derived.
8. In multilevel inheritance one class inherits ___
a) Only one class
b) More than one class
c) At least one class
d) As many classes as required
Answer
Answer: a [Reason:] The classes inherit only from one class. This continues as each class inherits only one class. There should not be any class which inherits from two or more classes or which have more than one subclass.
9. All the classes must have all the members declared private to implement multilevel inheritance.
a) True
b) False
Answer
Answer: b [Reason:] There is no mandatory rule to make the members private for multilevel inheritance. Moreover if all the classes have only the private members then there won’t be any member to get inherited. Hence the working will be of no use.
10. Can abstract classes be used in multilevel inheritance?
a) Yes, always
b) Yes, only one abstract class
c) No, abstract class doesn’t have constructors
d) No, never
Answer
Answer: a [Reason:] The abstract classes can always be used in multilevel inheritance. The only condition that may arise is that all the undefined functions must be defined in subclasses. There must not be any undefined function.
11. How many abstract classes can be used in multilevel inheritance?
a) Only 1
b) Only 2
c) At least one less than number of levels
d) Can’t be used
Answer
Answer: c [Reason:] At least one class must implement all the undefined functions. Hence there must be at least one class which is not abstract. That is at least one less than number of levels.
12. If all the classes used parameterized constructors and no default constructor then, _____
a) The object of lower level classes can’t be created
b) Object of lower level classes must call parent class constructors explicitly
c) Object of lower level classes must define all the default constructors
d) Only object of first class can be created, which is first parent
Answer
Answer: b [Reason:] Each class constructor must be called before creating object of any subclass. Hence it will be mandatory to call the constructors of parent classes explicitly with parameters. This will make all the previous class member be initialized and then the class in use will be able to create the object.
13. In multilevel inheritance, which is the most significant feature of OOP used?
a) Code readability
b) Flexibility
c) Code reusability
d) Code efficiency
Answer
Answer: c [Reason:] The classes using multilevel inheritance will use the code in all the subsequent subclasses if available. Hence the most significant feature among the options given is code reusability. This feature is generally intended to use the data values and reuse the redundant functions.
14. Does following code show multiple inheritance?
class A { int a; }; class B { int b; }; class C:public A, public B { int c; }; class D:public C { int d; };
a) Yes, class C and class D
b) Yes, All together it’s multilevel
c) No, 4 classes are used
d) No, multiple inheritance is used with class A, B and C
Answer
Answer: d [Reason:] Since multiple inheritance is used to derive class C and then class D is derived from class C. This is not multilevel inheritance. The classes should derive from single class. This is actually hybrid inheritance.
15. Is it compulsory for all the classes in multilevel inheritance to have constructors defined explicitly if only last derived class object is created?
a) Yes, always
b) Yes, to initialize the members
c) No, it not necessary
d) No, Constructor must not be defined
Answer
Answer: c [Reason:] It’s not mandatory to define the constructors explicitly. Default constructor will always be provided by the compiler itself if none another constructor is defined in those classes. If explicit default constructor is defined it will be used.
Object Oriented MCQ Set 5
1. Multiple inheritance is ____
a) When a class is derived from another class
b) When a class is derived from two or more classes
c) When a class is derived from other two derived classes
d) When a class is derived from exactly one class
Answer
Answer: b [Reason:] The multiple inheritance is used when a class is being derived using two base classes or more. This way a single class can have features of more than one classes inherited into a single unit. This lets us combine two class members into a single class.
2. Which problem arises due to multiple inheritance, if hierarchical inheritance is used previously for its base classes?
a) Diamond
b) Circle
c) Triangle
d) Loop
Answer
Answer: a [Reason:] The diamond problem arises when multiple inheritance is used. This problem arises because the same name member functions get derived into a single class. Which in turn creates ambiguity in calling those methods.
3. How many classes should a program contain to implement the multiple inheritance?
a) Only 1
b) At least 1
c) At least 3
d) Exactly 3
Answer
Answer: c [Reason:] For the implementation of multiple inheritance, there must be at least 3 classes in a program. At least 2 base classes and one class to inherit those two classes. If lesser, it becomes single level inheritance.
4. Which programming language restricts the use of multiple inheritance?
a) C++
b) PHP
c) SmallTalk
d) Java
Answer
Answer: d [Reason:] Java doesn’t allow use of multiple inheritance with classes. But this can be done by using the interfaces. This is more secure and unambiguous way to implement multiple inheritance.
5. Is it possible to have all the abstract classes as base classes of a derived class from those?
a) Yes, always
b) Yes, only if derived class implements all the methods
c) No, because abstract classes doesn’t have constructors
d) No, never
Answer
Answer: b [Reason:] The condition for abstract class applies same here too. All the undefined functions must be defined. Hence all the base classes can be abstract but derived class must implement all those undefined functions.
6. If class A inherits class B and class C as “class A: public class B, public class C {// class body ;}; ”, which class constructor will be called first?
a) Class A
b) Class B
c) Class C
d) All together
Answer
Answer: b: [Reason:] The constructors of parent class will be called first. In that, the constructor of the classes will be called in the same sequence as that mentioned in class definition inheritance. Since class B is mentioned first for inheritance, its constructor will be called first.
7. Why does diamond problem arise due to multiple inheritance?
a) Methods with same name creates ambiguity and conflict
b) Methods inherited from the super class may conflict
c) Derived class gets overloaded with more than two class methods
d) Derived class can’t distinguish the owner class of any derived method
Answer
Answer: a [Reason:] All the derived classes can distinguish the base class members, but if a method is being inherited to the base classes from another class which again gets inherited into same class (diamond shape), that may create conflict in using the function from two available.
8. How many base classes can a derived class have which is implementing multiple inheritance?
a) Only 2
b) At least 2
c) At most 2
d) As many as required
Answer
Answer: d [Reason:] The classes can derive from as many classes as required since the multiple inheritance feature is made to combine or group together the functions that are from different classes. This make the derived class stronger in terms of its flexibility.
9. How to overcome diamond problem ?
a) Using alias name
b) Using seperate derived class
c) Using virtual keyword with same name function
d) Can’t be done
Answer
Answer: c [Reason:] To overcome the ambiguity and conflict we can use keyword virtual. This will help us to differentiate the functions with same name that came to last derived class in diamond problem.
10. When multiple inheritance is used, which class object should be used in order to access all the available members of parent and derived class ?
a) Derived class object
b) Parent class objects
c) Use Abstract derived class
d) Derive a class from derived class
Answer
Answer: a [Reason:] The derived class object can access all of its own members. It can also access the available members of the parent classes, because the members are derived into the derived class.
11. If all the members of all the base classes are private then,
a) There won’t be any use of multiple inheritance
b) It will make those members public
c) Derived class can still access them in multiple inheritance
d) Compile time error
Answer
Answer: a [Reason:] The derived class will not be able to access any members of the base classes. Since private member’s are not inheritable. It leads to no use of multiple inheritance.
12. Is it compulsory to have constructor for all the classes involved in multiple inheritance?
a) Yes, always
b) Yes, only if no abstract class is involved
c) No, only classes being used should have a constructor
d) No, they must not contain constructors
Answer
Answer: b [Reason:] The constructors must be defined in every class. If class is abstract, it won’t have any constructor but other classes must have constructor. Either implicit or explicit.
13. If a class contains 2 nested class and is being inherited by another clsss, will there be any multiple inheritance?
a) No, only single level inheritance is used
b) No, only multilevel inheritance is used
c) Yes, because 3 classes are involved
d) Yes, because more than 1 classes are being derived
Answer
Answer: a [Reason:] When a class having nested classes is being derived into another class. It indirectly means a simple class is being inherited to another class. This is single level inheritance.
14. Which members can’t be accessed in derived class in multiple inheritance ?
a) Private members of base
b) Public members of base
c) Protected members of base
d) All the members of base
Answer
Answer: a [Reason:] The private member’s are available for only the class containing those members. Derived classes will have access to protected and publicembers only.
15. Can the derived class be made abstract if multiple inheritance is used ?
a) No, because other classes must be abstract too
b) Yes, if all the functions are implemented
c) Yes, if all the methods are predefined
d) No, since constructors won’t be there
Answer
Answer: d [Reason:] The derived class must not be abstract. This is because the abstract classes doesn’t have constructor and hence we won’t be having capability to have instances. This will restrict use of multiple inheritance.
