OOPS Multiple Choice Questions

OOPS Multiple Choice Questions

1) Which of the following language was developed as the first purely object programming language?

SmallTalk

C++

Kotlin

Java 

Answer: a. SmallTalk

Explanation: This programming language was invented as the first pure OOPS (object-oriented) language. This language was designed by Alan Kay in the early 1970s.

2) Who developed object-oriented programming?

Adele Goldberg

Dennis Ritchie

Alan Kay

Andrea Ferro 

Answer: c. Alan Kay

Explanation: In the year 1970, Alan Kay gave Object-Oriented programming. He coined the concept of OOPS at a grad school in the year 1966 or 1967. Alan kay, Adele Goldberg, Dan Ingalls and others developed the first Smalltalk programming language, which follows the OOPS concept.

3) Which of the following is not an OOPS concept?

Encapsulation

Polymorphism

Exception

Abstraction 

Answer: c. Exception

Explanation: None.

4) Which feature of OOPS described the reusability of code?

Abstraction

Encapsulation

Polymorphism

Inheritance 

Answer: d. Inheritance

Explanation: Inheritance is the feature of OOPS, which allows the users of OOPS to reuse the code which is already written. This OOPS feature inherits the features of another class in the programs. This mechanism actually inherits the fields and methods of the superclass.

5) Which of the following language supports polymorphism but not the classes?

C++ programming language

Java programming language

Ada programming language

C# programming language 

Answer: c. Ada programming language

Explanation: It is a programming language that disapproves of the concept of polymorphism but supports the concept of classes. It is an object-based language. So, it does not follow the Object-oriented programming concepts.

6) Which among the following feature is not in the general definition of OOPS?

Modularity

Efficient Code

Code reusability

Duplicate or Redundant Data 

Answer: d. Duplicate or Redundant Data

Explanation: Duplicacy or Redundancy of data is a feature which totally dependent on the programmers. So, it cannot be created by the OOPS.

7) Which feature of OOPS derives the class from another class?

Inheritance

Data hiding

Encapsulation

Polymorphism 

Answer: a. Inheritance

Explanation: Inheritance is an important OOPS feature which derives the class from the base class or superclass. This OOPS feature inherits the features of another class in the programs. This mechanism actually inherits the fields and methods of the superclass.

8) Define the programming language, which does not support all four types of inheritance?

Smalltalk

Kotlin

Java

C++ 

Answer: c. Java

Explanation: Java is a programming language that disapproves of the concept of 'multiple inheritance'. So, it does not agree with all types of inheritance. But, we can implement 'multiple inheritance' in Java language using the interface concept.

9) A single program of OOPS contains _______ classes?

Only 1

Only 999

Only 100

Any number 

Answer: d. Any number

Explanation: We can define any number of classes with different names in a single program of OOPS.

10) Which operator from the following can be used to illustrate the feature of polymorphism?

Overloading <<

Overloading &&

Overloading | |

Overloading += 

Answer: a. Overloading <<

Explanation: << is an insertion operator which is used for overloading (polymorphism).

11) Which two features of object-oriented programming are the same?

Abstraction and Polymorphism features are the same

Inheritance and Encapsulation features are the same

Encapsulation and Polymorphism features are the same

Encapsulation and Abstraction 

Answer: d. Encapsulation and Abstraction

Explanation: Encapsulation and Abstraction are the same OOPS concepts. Encapsulation hides the features of the object and binds all the properties inside a single class. And abstraction is a feature that shows the required data to the user.

12) Which header file is required by the C++ programming language to use the OOPS concept?

stdio.h

iostream.h

stdlib.h

We can easily use the OOPS concepts in c++ programs without using any header file. 

Answer: d. We can easily use the OOPS concepts in c++ programs without using any header file.

Explanation: There is no need to use any particular header file for using the OOPS concept in the C++ programs. The C++ functions and variables have their respective header files, which should be defined in the program.

13) Which of the following definition is incorrect for polymorphism?

Polymorphism helps in redefining the same functionality

Polymorphism concept is the feature of object-oriented programming (OOP)

It always increases the overhead of function definition

Ease in the readability of the program 

Answer: c. It always increases the overhead of function definition

Explanation: This concept of OOPS never increases the overhead of function definition.

14) Which among the following cannot be used for the concept of polymorphism?

Static member function

Constructor Overloading

Member function overloading

Global member function 

Answer: a. Static member function

Explanation: These functions are not an object property. That's why they cannot be acceptable for overriding or overloading.

15) Which function best describe the concept of polymorphism in programming languages?

Class member function

Virtual function

Inline function

Undefined function 

Answer: b. Virtual function

Explanation: Only those functions are used to achieve the polymorphism, which are declared as 'virtual'. These functions let the OOPS programs decide at runtime which function is to be called by the pointer.

16) Which member function is assumed to call first when there is a case of using function overloading or abstract class?

Global function

Local function

Function with lowest priority

Function with the highest priority 

Answer: d. Function with the highest priority

Explanation: The member function with the highest priority is called first when there is function overloading, or abstract class is used.

17) Is it true to use polymorphism in the C programming language?

True

False 

Answer: a. True

Explanation: Yes, we can use the concept of polymorphism in the C programming language. Users can use structures and then declare pointers in C programming language, which in turn points to some function.

Here, he/she can easily simulate the functions which are not exactly member function. Hence, users can manipulate the concept of polymorphism in the C language.

18) Which of the following language uses the classes but not the polymorphism concept?

Procedure Oriented language

Object-based language

Class-based language

If classes are used, then the polymorphism concept will always be used in the programming languages. 

Answer: b. Object-based language

Explanation: Object-based languages are those languages which support the definition of classes but not the polymorphism. Inheritance is also another feature which is not supported by these languages.

19) Which of the following OOP concept is not true for the C++ programming language?

A class must have member functions

C++ Program can be easily written without the use of classes

At least one instance should be declared within the C++ program

C++ Program must contain at least one class 

Answer: d. C++ Program must contain at least one class

Explanation: Use of class in the C++ language is not mandatory. Programs can be easily written without the use of classes. C++ programs classes may or may not contain the member function. That's why it is not a necessary situation in the C++ language.

20) What is the extra feature in classes which was not in the structures?

Member functions

Data members

Public access specifier

Static Data allowed 

Answer: a. Member functions

Explanation: Member function is an extra feature which is allowed in class but not in the concept of structures.

21) How many types of polymorphism in the C++ programming language?

Three types of polymorphism

Two types of polymorphism

Five types of polymorphism

Four types of polymorphism 

Answer: b. Two types of polymorphism

Explanation: C++ programming language has two types of polymorphism: 1. Runtime Polymorphism 2. Compile-time Polymorphism

Runtime Polymorphism: It is meet by the function overriding. This polymorphism is also known as late or dynamic binding.

Compile-time Polymorphism: It is meet by the operator and function overloading. This polymorphism is also known as early or static binding.

22) Which of the following feature is also known as run-time binding or late binding?

Dynamic typing

Dynamic loading

Dynamic binding

Data hiding 

Answer: c. Dynamic binding

Explanation: Dynamic binding or runtime binding or late binding is that type of binding which happens at the execution time of the program or code. Function or method overriding is the perfect example of this type of binding. Virtual functions are used to achieve the concept of function overriding.

23) Which among the following is not a member of the class?

Virtual function

const function

Static function

Friend function 

Answer: d. Friend function

Explanation: The public member functions of a class can easily access the private data members of the same class.

This is achieved by the "friend", which is a non-member function to the class. Its private data can be accessed. That's why the friend function is not a member of the class.

24) Which of the following class is known as the generic class?

Final class

Template class

Abstract class

Efficient code 

Answer: b. Template class

Explanation: Template classes are those classes which can be used for any value of data type. So, these are known as a generic class.

Template classes help in making the genetic classes and generate the objects of classes based on the parameters. This type of class also saves system memory.

25) Which operator overloads using the friend function?

*

( )

->

= 

Answer: a. *

Explanation: The operators ( ->, ( ), =) cannot be overloaded using the friend function because if they are overloaded, then the code will show the compilation error. That's why * (asterisk) is a symbol that can be overloaded using the friend function.

26) Which of the following OOP concept binds the code and data together and keeps them secure from the outside world?

Polymorphism

Inheritance

Abstraction

Encapsulation 

Answer: d. Encapsulation

Explanation: Encapsulation is an important concept of Object-oriented programming. This concept binds the data and methods in a single unit. It binds the methods which manipulate the data.

27) Which member of the superclass is never accessible to the subclass?

Public member

Protected member

Private member

All of the mentioned 

Answer: c. Private member

Explanation: Private is a member of a class which never be accessible to the derived class.

28) What is the size of a class?

Sum of the size of all inherited variables along with the variables of the same class

The size of the class is the largest size of the variable of the same class

Classes in the programming languages do not have any size

Sum of the size of all the variables within a class. 

Answer: c. Classes in the programming languages do not have any size

Explanation: The object size defines the size of the class. That's why classes do not have any size.

29) Which class cannot create its instance?

Parent class

Nested class

Anonymous class

Abstract class 

Answer: d. Abstract class

Explanation: The instance of the abstract class can't be created because it will not have any constructor of its own. Hence while creating an instance of a class, it can't initialize the object members.

30) Encapsulation adds the function in a user-defined structure.

True

False 

Answer: b. False

Explanation: The encapsulation concept does not add the function in a user-defined structure because if the member functions are involved, then the user cannot call the structures defined by it.

31) Which of the following variable violates the definition of encapsulation?

Array variables

Local variables

Global variables

Public variables 

Answer: c. Global variables

Explanation: Global variable is a variable which violates the definition of encapsulation. The definition of encapsulation defines that the data or variable should be accessed by the specified set of elements. But, the global variable is accessible everywhere in the code. This type of variable does not hide the internal performance of the code. That's global variable violates the encapsulation concept.

32) How can the concept of encapsulation be achieved in the program?

By using the Access specifiers

By using the concept of Abstraction

By using only private members

By using the concept of Inheritance 

Answer: a. By using the Access specifiers

Explanation: Users can achieve the concept of encapsulation by implementing the access specifiers in the code. It is not compulsory that the user use only private members.

33) The concept of encapsulation helps in writing which type of classes in the Java programming language?

Abstract classes

Wrapper classes

Mutable classes

Immutable classes 

Answer: d. Immutable classes

Explanation: The concept of encapsulation helps in writing immutable classes in the Java programming language because these classes are used for caching purposes.

34) Encapsulation is_____?

technique of combining more than one member functions into a single unit.

mechanism of combining more than one data member into a single unit.

mechanism of combining more than one data members and member functions that implement on those data members into a single unit

technique of combining more than one data members and member functions into a single unit, which can manipulate any data. 

Answer: c. mechanism of combining more than one data members and member functions that implement on those data members into a single unit

Explanation: Encapsulation is an OOPS mechanism that combines more than one data member and member function and implements the member functions on those data members into a single unit.

35) Which of the following statement of a program is not right?

class teacher{ }; teacher s[5];

class teacher{ }s;

class teacher{ }; teacher s;

class teacher{ }s[]; 

Answer: d. class teacher{ }s[];

Explanation: This statement is false because it must be compulsory to specify the array with its size.

36) Which of the following syntax is incorrect for the class definition?

student class{ };

class student{ student(int a){} };

class teacher{ public: teacher(int a){ } };

None of the mentioned 

Answer: a. student class{ };

Explanation: In this syntax, the keyword 'class' is present after the student. That's why this syntax is incorrect.

37) The object cannot be________?

passed by copy

passed as function

passed by value

passed by reference 

Answer: b. passed as function

Explanation: The object cannot be passed as the function because it is an instance of a class. Only the objects passed by the value, reference or copy.

38) Which among the following feature does not come under the concept of OOPS?

Data binding

Data hiding

Platform independent

Message passing 

Answer: c. Platform independent

Explanation: Platform independence is a feature which does not come under the OOPS concepts. This feature depends on the programming language. C++ is an object-oriented programming language which is not a platform-independent language.

39) Which of the following feature may be breaked if the user does not use the classes in the code?

Object must be used violated

Only the encapsulation concept is violated

Inheritance cannot be implemented

Basically, all the features of OOPS get violated 

Answer: d. Basically, all the features of OOPS get violated

Explanation: If the user does not use the classes in the code, then all the OOP features get violated. And, the encapsulation and inheritance cannot be implemented without the use of classes.

40) Which of the following feature interacts one object with another object?

Message reading

Message passing

Data transfer

Data binding 

Answer: b. Message passing

Explanation: Message passing is a feature of OOP that connects one object with another object.

It is a concept of communication for passing the messages between the two objects. It allows objects to send and receive information among them.

41) Which definition best defines the concept of abstraction?

Hides the important data

Hides the implementation and showing only the features

Hiding the implementation

Showing the important data 

Answer: b. Hides the implementation and showing only the features

Explanation: It hides the implementation part and showing only the data and features which are required to the end-user.

This technique is used to hide the complexity of code and its details from the user. It is also used to define a good interface in coding.

42) The combination of abstraction of the data and code is viewed in________.

Inheritance

Object

Class

Interfaces 

Answer: b. Object

Explanation: Object is a technique which can be viewed as an abstraction of the combination of data and code. This OOPS concept uses the class data members and their functioning as the data abstraction. Code abstraction is used as the object of an inbuilt class.

43) The principle of abstraction___________

is used to achieve OOPS.

is used to avoid duplication

Use abstraction at its minimum

is used to remove longer codes 

Answer: b. is used to avoid duplication

Explanation: The principle of abstraction is used to avoid the code duplicacy. In this technique, the program does not contain any redundant functions. And it also makes the program effective.

44) Which among the following concept is correct if a user using the concept of encapsulation in a code?

The modification of the code can be additional overhead

Member functions can be used for modifying the data type of data members

The data type of data member cannot be modified.

The data type of the data member can be easily modified without modifying any other code 

Answer: d. The data type of the data member can be easily modified without modifying any other code

Explanation: Data type of a data member can be easily modified without modifying any code. Member functions can never modify the data type of the data members in the same class.

45) Using the concept of encapsulation security of the data is ___________

Ensured to some extent

Purely ensured

Not ensured

Very low 

Answer: a. Ensured to some extent

Explanation: The concept of encapsulation can only ensure data security to some extent.

46) Consider the following Java program and select the right option from the given options.

class marksofstudent

{

int subjectmarks;

public : int* fun()

{

return &subjectmarks;

}

};

main()

{

marksofstudent s;

int *ptr = c.fun() ;

return 0;

} class marksofstudent { int subjectmarks; public : int* fun() { return &subjectmarks; } }; main() { marksofstudent s; int *ptr = c.fun() ; return 0; }

The above program violates the feature of encapsulation

The above program may result in undesirable conditions

The above program will generate an error

The above program is good to go 

Answer: a. The above program violates the feature of encapsulation

Explanation: The code in this question violates the definition of encapsulation.

47) The name of the default access specifier for the member functions or data members in the C++ programming language is_________.

Private access specifier

Public access specifier

Protected access specifier

Depends on compiler 

Answer: a. Private access specifier

Explanation: If none of the access specifiers is used, then the data members and member functions are Private by default in C++ classes. This specifier is actually used to increase the privacy of information.

48) Which of the following option best illustrates a friend class?

This class can access and manipulate all the private members of that class which connects to a friend.

Friend class can only access and manipulate the protected data members of that class that connects to a friend.

Friend class can't access any data member of another class but can use its methods

Friend class don't have any implementation 

Answer: a. Friend class can access and manipulate all the private members of the class, of which it is a friend

Explanation: A friend class can easily access all the private data members of another class.

49) Which of the following definition best describes the concept of polymorphism?

It is the ability to process the many messages and data in one way

It is the ability to process the undefined messages or data in at least one way

It is the ability to process the message or data in more than one form

It is the ability to process the message or data in only one form 

Answer: c. It is the ability for a message or data to be processed in more than one form.

Explanation: None.

50) Which class/ or set of classes can describe the concept of polymorphism in the following code?

abstract class student_details

{

public : int marksofstudent;

calculate_grade();

}

class topper:public student_details

{

public : calculate_grade()

{

return 15;

}

};

class average:public student_details

{

public : calculate_grade()

{

return 30;

}

};

class failed{ int marksofstudent; }; abstract class student_details { public : int marksofstudent; calculate_grade(); } class topper:public student_details { public : calculate_grade() { return 15; } }; class average:public student_details { public : calculate_grade() { return 30; } }; class failed{ int marksofstudent; };

Only the student_details class can show the concept of polymorphism

The class which is 'failed' should also inherit class student for this code to work for polymorphism

The student_details, topper and average classes together can show the concept of polymorphism

Only the student_details and topper class together can show the concept of polymorphism 

Answer: c. The student_details, topper and average classes together can show the concept of polymorphism

Explanation: None.