OOP’s Interview Questions 2024
What is Class?
In object-oriented programming, a class is a blueprint for creating objects (instances). It defines the properties (attributes) and behaviors (methods) that objects
of that type will have.
What is Object?
An object is an instance of a class. It encapsulates data (attributes) and behaviors (methods) defined in its class.
What is Inheritance?
Inheritance is a mechanism in which a new class (derived class/subclass) is created by inheriting properties and behaviors from an existing class (base
class/superclass).
What is Purpose of Inheritance?
The purpose of inheritance is to promote code reusability and
to establish a relationship between classes where the subclass inherits the attributes and methods of the superclass. This helps in organizing and structuring code in a
hierarchical manner.
Explain the Use of Inheritance?
Inheritance allows subclasses to reuse and extend the functionality of superclasses. It facilitates the creation of specialized classes while maintaining
common functionality defined in a superclass.
What is method Overriding.
Overriding is a feature of inheritance where a subclass provides a specific implementation of a method that is already provided by its superclass. It allows a subclass to provide its own implementation of a method defined in the superclass.
What is method Overloading?
Overloading refers to defining multiple methods with the same name but with different parameters or signatures within the same class. This allows a method to perform different tasks based on the number or type of parameters passed to it.
What is Polymorphism with Example?
Polymorphism is the ability of objects of different classes to be treated as objects of a common superclass. For example, consider a superclass “Shape” with subclasses “Circle” and “Rectangle”. Both “Circle” and “Rectangle” can be treated as “Shape” objects when a method expects a “Shape” parameter.
What is Example of Inheritanc?
An example of inheritance would be a superclass “Vehicle” with subclasses like “Car”, “Truck”, and “Motorcycle”. These subclasses inherit common properties and behaviors from the “Vehicle” class while also having their own specific attributes and methods.
Explain Operator Overloading?
Operator overloading is a feature that allows redefining the behavior of operators such as “+”, “-“, “*”, etc., for use defined types. It enables extending the functionality of operators beyond their predefined functionality.
What is Abstraction?
Abstraction is the process of hiding the implementation details and showing only the essential features of an object. It helps in reducing complexity and focusing on relevant aspects of an object.
What is Example of Abstraction?
An example of abstraction would be a “Car” class exposing methods like “start()”, “accelerate()”, and “stop()”, hiding the internal details of how these methods are implemented.
What is Data Binding?
Data binding is the process of connecting the application UI (User Interface) with the application logic. It establishes a connection between the data model (backend) and the UI components, ensuring that changes in one are automatically reflected in the other.
What is Encapsulation?
Encapsulation is the bundling of data (attributes) and methods (behaviors) that operate on the data into a single unit (class). It restricts direct access to the data and ensures that data is accessed and modified through well-defined methods.
Example of Encapsulation?
An example of encapsulation would be a “Person” class with private attributes like “name”, “age”, and “gender”, and public methods like “setName()”, “setAge()”, and “getGender()” to manipulate and access these attributes.
What is Instance?
A particular occurrence of an object created from a class blueprint in object oriented programming.
What is a constructor?
A constructor is a special type of method in a class that is automatically called when an object of that class is created. Its purpose is to initialize the object’s state by assigning initial values to its attributes.
What is the difference between a constructor and a method?
Constructors are used to initialize objects when they are created, while methods are functions within a class that define behaviors or actions that objects of that class can perform. Constructors have the same name as the class and do not have a return type, whereas methods can have any name and return type.
What is a destructor?
A destructor is a special method that is called when an object is destroyed or goes out of scope. It is used to release resources or perform cleanup tasks before the object is deallocated from memory.
Explain the difference between stack and heap memory?
Stack memory is used for storing local variables and function call information, and its memory is managed automatically by the compiler. Heap memory is used for dynamically allocated memory, and its memory needs to be managed manually by the programmer.
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What is the difference between pass by value and pass by reference?
Pass by value involves passing a copy of the actual parameter to a function, while pass by reference involves passing the memory address of the actual parameter. Pass by value creates a new copy of the parameter, while pass by reference allows direct modification of the original parameter.
What is a static variable?
A static variable is a variable that retains its value across function calls and exists for the entire duration of the program. It is initialized only once and is shared among all instances of the class.
What is a virtual function??
A virtual function is a member function in a base class that is declared using the virtual keyword and can be overridden by a derived class. It allows dynamic binding or late binding at runtime.
What is the difference between compile-time polymorphism and runtime
polymorphism?
Compile-time polymorphism, also known as static polymorphism, is achieved through function overloading and operator overloading, where the compiler selects the appropriate function or operator at compile time based on the parameters. Runtime polymorphism, also known as dynamic polymorphism, is achieved through function overriding and is resolved a runtime based on the actual type of the object.
What is the difference between an abstract class and an interface?
An abstract class can have both abstract (unimplemented) and concrete (implemented) methods, while an interface can only have abstract method declarations. Additionally, a class can implement multiple interfaces but can inherit from only one abstract class.
What is exception handling?
Exception handling is a mechanism used to handle runtime errors or exceptional situations in a program. It allows the program to gracefully recover from errors by catching exceptions and taking appropriate actions, such as displaying an error message or performing cleanup tasks.
What is a try-catch block?
A try-catch block is used in exception handling to catch and handle exceptions that may occur within a block of code. The code within the try block is monitored for exceptions, and if an exception occurs, it is caught by the catch block, where appropriate actions can be taken.
What is the difference between procedural and object-oriented programming?
Procedural programming focuses on writing procedures or functions that perform operations on data, while object-oriented programming focuses on creating objects that encapsulate data and behaviors. Object-oriented programming promotes code reuse, modularity, and extensibility through concepts like encapsulation, inheritance, and polymorphism.
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