Best 35+ Oops Interview Questions and Answers

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Here we are going to tell you those oops interview questions and answers which every employer asks the candidate in an interview. So let’s know about those oops interview questions, if you give the right answers, the chances of getting jobs are increased.

The way to get any job is through interviews. If you do not give correct answers to all the questions in the interview, then it is difficult to get a job. So read all the oops interview questions and answers carefully hope you will love this all in one bundle on oops interview questions.

Oops interview questions and answers

1) What is OOPS in Brief?

πŸš€ Two types of program paradigm are used in Programming. These procedures are Oriented and Object-oriented programming. All new-time programming languages use Object-oriented programming. OOPs, are a software development paradigm used to solve problems encountered in a process-oriented approach.(Most asked oops interview questions)

Object-oriented programming does not allow data to flow into the system during program development. This prevents it from sudden change by any other function. In this, the problem is solved by an object, and in this data and function work with the object. Only the object’s function can access the object’s data.

Thus, it can be said that Object-oriented programming is a programming approach in which data and functions are tied together called classes and used by objects. Where its data and functions are different store and process for each object. Here, memory space is allocated for the object in which its data and functions are stored.

2) Describe the advantages of OOPS concepts

πŸš€ Object-Oriented Programming Language has the following benefits: –

In this method, redundant code can be removed by Inheritance and the use of already existing Classes can be extended.

The Concept of Data Hiding helps programmers to create secure programs that cannot be used by code in other parts of the program.

With the technique of OOP, a program can be divided into several parts based on groups of objects for quick (quick) operational.

With this technique, large programs can be easily prepared by the combination of small programs.

The level modules employed by this easily relate to other modules, which do not have to write the code again and again, due to which the program saves time and increases the ability to develop.

This technology also integrates their related functions with Object Classes, which makes processing work easier and safer.

The message passing method for communication between objects is easy to interface with the External System.

Software programming can easily solve this complexity.

Software is easy to develop.

3) Properties of OOPS

πŸš€ In this type of programming, programs are seen as tasks to be performed.

More than one function is written to perform these functions.

Data can be easily sent from one function to another.

Object-oriented programming has been developed to diagnose all these problems.

In this, data is considered as an important component of program development rather than function.

Data are associated with the function in which they are used.

Data in the system is not allowed to be changed independently by the External Function.

The data and the functions operating on it are close to each other.

And it protects against accidental alteration of data by an external function.

Read more: Operating System MCQs

Oops concepts interview questions

4) Write basic concepts of OOPS?

πŸš€ The following are the features of the Object-Oriented Programming Language, and its Basic Concept is as follows (Most asked oops interview questions):
Data abstraction and encapsulation
Dynamic Binding
Message Passing

5) What is an Object?

πŸš€ It is the basic run-time entity of OOPs. This represents an object (person, place, a bank account, etc.). An object is the variable of the class that executes the class and processes the data using the methods available in it. Once the object is created, it takes up space like other variables in memory.

6) What is a class?

πŸš€ Class is a user-defined data type that contains data and code that is used by the object. A class is a structure that defines the object’s working. Many objects can be created after creating a class. Thus it can be said that class is a collection of objects of the same type.

7) What is Encapsulation and data abstraction?

πŸš€ Binding data and functions together are called Encapsulation. This is the most important feature of the class. In this, the data cannot be accessed outside the class, only the functions of the class can access it. The data abstraction is from inputting and outputting data without background process details in which it is performed by the functions of the class.(Most asked oops interview questions)

8) What is Inheritance?

πŸš€ This is an important feature of OOPs that provides the facility of one class to access the features of another class. In this, the object of one class can access and use the properties of other classes as well. It implements the feature of reusability where a new class is created to add new features to a class and also implement features of the old class in it, as well as new codes are added to the new class.

9) What is Polymorphism?

πŸš€ This is also an important concept of OOPs that gives the facility to create and use more than one form. It is performed by both function and operators where the function name or operator remains the same, but when the number or types of arguments or types of operands are different, they are used differently and perform the task. For example, the + operator is used to add numerical addition and strings.(Most asked oops interview questions)

10) What is static polymorphism?

πŸš€ Compile-time polymorphism is also called method overloading or early binding or static polymorphism.
This polymorphism means that we declare methods of the same name with different signatures because we can perform different tasks with the same method name.(Most asked oops interview questions)

11) What is dynamic polymorphism?

πŸš€ This type of polymorphism is called late binding or dynamic binding or method overriding. This polymorphism means that we declare methods of the same name with the same signature.

12) What is Dynamic Binding?

πŸš€ In OOPs inheritance and polymorphism implement this feature in which Binding or linking procedure is performed when called. This is called dynamic binding.

13) What is Message Passing?

πŸš€ Objects in OOPs communicate. Communicate by sending and receiving objects information. In OOPs, the message passing function is performed during a call. In which the information is input into the object through the function in the form of a function argument and the method of the object gives it the process to generate the result.

Oops interview questions and answers for fresher

14) What are the different types of inheritance?

πŸš€ There are five types of inheritance (most asked oops interview questions)

15) Define Single inheritance

πŸš€ When one class is inherited by another class, that inheritance is called single inheritance. In this, the property of one class is taken by another class. It has only one superclass and one subclass.

Oops interview questions and answers

Oops interview questions and answers

16) Define multiple inheritances

πŸš€ When more than one class is inherited by a class, that inheritance is called multiple inheritances. In this, the property of more than one class is inherited by one class. It consists of more than one superclass and one subclass.

Oops interview questions and answers

Oops interview questions and answers

17) Define multilevel inheritance

πŸš€ When more than one class inherits each other at a level, that inheritance is called multilevel inheritance. In this, a class inherits another class and the class that inherits the class becomes a subclass and the same subclass is inherited by another class. Similarly, all classes inherit each other.

Oops interview questions and answers

Oops interview questions and answers

18) Define Hierarchical inheritance

πŸš€ When a base class is inherited by more than one subclass, that inheritance is called hierarchical inheritance. In this, the property of one class is taken by more than one class. Hierarchical inheritance consists of one base class and more than one subclass. This is the opposite of multiple inheritances.

Oops interview questions and answers

Oops interview questions and answers

19) Define Hybrid inheritance

πŸš€ When we mix any two types of inheritance in our program, it is called hybrid inheritance. This inheritance is a combination of more than one inheritance. That is, it consists of two or more inheritance.

Oops interview questions and answers

Oops interview questions and answers

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20) The short difference in overloading and overriding

πŸš€ Method Overriding This is a type of polymorphism, but due to the separation of function overloading, it is created separately.

Just as in function overloading, member functions with the same name were created differently, member functions of the same name are created in different classes in Function or Method Overriding.(Most asked oops interview questions)

21) What are a sub and superclass?

πŸš€ The class that is derived from another class is called subclass and the class from which subclass is derived is called a superclass.
Superclass is also called base class and the subclass is also called the derived class.

oops interview questions c++

22) What is an Inline function?

πŸš€ Inline Function provides the solution to the process of calling a function in C ++, the word invoke is written in front of the function to make any function inline.

The calling of the inline function is direct and the inline keyword does not send a command to the compiler to request to allow it to work but in some situation, inline expansion does not work like-

(i) If the inline function is Recursive.
(ii) The function has a static value.
(iii) If the value is returning inside the function and has used switch or go to.

The inline function can be defined by expanding on the line in which it is invoked(Most asked oops interview questions).

23) What is a virtual function?

πŸš€ Virtual Function is used to derive run time polymorphism. If we have two classes, one base class, and the other derived class and we want to access the object of the derived class using pointer then it is not possible because the pointer of base class will always execute the function of a base class.

A virtual function is used to solve this problem. The function of the base class is virtualized, for which the word Virtual is written next to the base class. When a function is made virtual, the C ++ base pointer determines which function to run from the object pointed to. most asked oops interview questions)

24) What is a friend function?

πŸš€A friend function is used with the keyword β€˜friend’. A friend function is a useful function for c ++. Friend Function; The class in which he has been declared is not a member of that class but a β€˜friend’. Declare is done inside the Friend function class. Definitions of Friend function; is outside the class. These functions are not member functions of the class. These are non-member functions. (Most asked oops interview questions)

Features of Friend Function

The private function of the class is accessed by Friend Function.

When the member function was defined outside the class, then the scope resolution (: πŸ™‚ was used. Scope resolution (: πŸ™‚ is not used outside the class with friend function.

Member functions required an object to access, but since the friend function is a non-member function, it does not require any object to access it.
When a friend’s definition is created, then its parameters; there is an object (s) of class.

25) What is function overloading?

πŸš€ Function Overloading in C ++: This is a very good concept added to β€œC ++” which is named Function Overloading. That is, we can use the function of the same name in many ways. When we want to overload a function, then in reality many function names are the same, but their definitions are different.

Oops interview questions for Expert

26) What is operator overloading?

πŸš€ The way we can perform overloading of functions, similarly, we can also use different types of basic operators for many different tasks and this process is called operator overloading.

For example, if we want to add two values of int type a and b, then we use a + b Expression. But if we want to join the values of the Data Members of the objects of a class we created, then we can do this by operator overloading. With operator overloading, our program becomes easy to understand and fast in speed. Operators can be mainly divided into two parts:

27) Explain the term constructor

πŸš€ A constructor is a member function of a special type, which is similar to its class name. The class whose constructor is made, if the object of that class is created when it is automatically called. The constructor has no return type. Neither does void return.

If a value has to be initialized, it has to create its member function separately and access it with the object. The constructor does this work only after creating an object. A virtual keyword is not used with the constructor.

28) Define Destructor?

πŸš€ Destructor is a special type of member function, which destroys the object. When the object goes out of scope, then the Destructor automatically calls. Destructor; Similar to a constructor, but the Destructor does not have parameters. Destructor prefix is used with the ~ (tilde) sign.

29) What is an abstract class?

πŸš€ When there was an Abstract Class in C ++, no abstract keyword was used. But the class which had a pure virtual function inside it became a Class Abstract Class.

In Java, there is no keyword named virtual, but Abstract Class is also used in Java with abstract keyword. An abstract class is written with abstract keyword.(Most asked oops interview questions)

Syntax for Abstract Class
abstract class class_name (); // abstract class

30) What is a ternary operator?

πŸš€ Conditional Operator has three Expressions. Conditional Operator is also known as Ternary Operator. In this Operator, if the first expression is true, then it prints the second expression in output. If the first expression in the Conditional Operator is false, then it prints the third expression in the output.

Syntax for Conditional / Ternary Operator
expression1? Expression 2: expression 3

Oops interview questions Most Asked

31) What is the super keyword?

πŸš€ The super keyword use for calling parent class constructor with argument and without argument. it can also be used for calling methods from the parent class.

32) What is exception handling?

πŸš€ This is a type of error that occurs at run time or execution time. Exception handling is used when a specific code of the program cannot be handled or in case of an unusual situation.

These exceptions can also be divided by zero, out of the bound array, out of memory, or other reasons.

Exceptions are of two types.
Compile-time Error
Run-time exceptions

33) What are tokens?

πŸš€Just as the smallest unit of a paragraph is a word, similarly the smallest unit in C ++ is called a token. C ++ consists of the following tokens (Most asked oops interview questions).
Key Words

34) What is a pure virtual function?

πŸš€ If we define a function in the base class and its definition is given in derived class, then that function of a base class is of do-nothing type, this type of function is called Pure Virtual Function and such classes in which Pure Virtual Function Is called Abstract Class. (most asked oops interview questions)

35) What are the access modifiers?

πŸš€ Access Modifiers in C #: All Members of a Class can Directly Access any other Member. But we have to use different types of Access Modifiers Provided by C # to decide which Members of another Class can access and how they can access.

Access Modifiers can be used not only with a variety of C # Supported Types such as Classes, Interfaces, Structures, Enumerations, and Delegates, but also with the various Members to be defined. Access modifiers are always specified before the Member. 5 Access Modifiers are basically supported in C #.

36) What are the various types of constructors?

πŸš€ Its types are as follows: –

Default constructors: Default constructors are also called empty constructors because they have no arguments. It has no parameters.
If you do not specify any constructor, then the compiler automatically calls the default constructor. But the thing to remember is that the name of the constructor is the same as the name of the class. And we can never declare a constructor with the help of return type.

Parameterized constructors: It is also a constructor that has some arguments and its name is also similar to the class name. Generally, these arguments help in initializing that object when an object is created.

Copy constructors: In this constructor, we pass the object of the class to another object of the same class. As its name is a copy constructor, i.e. copying the values of one object to another object of the class.

And to copy the values, we have to pass the object whose values we have to copy and when we pass an object into constructors, we need to use & ampersand (address operator).


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Bikash Chhetri

Seasoned Digital Marketer with 1 year of experience building & implementing strategies focused on SEO, SMO, Link Building, and Keyword Research for small to medium size websites.

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  1. August 19, 2020

    […] Read More: oops interview questions and answers […]

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