Object-Oriented Programming

1.Define OOPS?

Object-Oriented Programming is a programming methodology which offers a new model where data and processes are integrated. e.g: C++, C#, Java

2.What is Encapsulation ?

Short Answer: Binds code and data

Long Answer: Encapsulation is the mechanism that binds together the code and data it manipulates into a single unit and keeps them safe from external interference and misuse.

In C++ this is supported by a construct called class.

3.What is Data Abstraction ?

Short Answer: Hide background details

Long Answer: The technique of creating a new data type that are well suited to an application to be programmed is known as data abstraction.

e.g: Stack – We can use push & pop without bothering how the push and pop operations performed.

The class is a construct in C++ for creating user-defined data types called Abstract Data Types (ADT’s)

4.What is Polymorphism ?

Short Answer: Polymorphism means the ability to assume several forms.

Long Answer: Polymorphism refers to the ability of an entity to refer to objects of various classes at runtime.

5.What is Inheritance ?

Short Answer: Extension & reuse of existing code

Long Answer: Inheritance allows the extension & reuse of existing code (class) without having to rewrite the code from scratch. Inheritance involves the creation of a new class (derived class) from the existing ones (base classes)

The new derived class inherits the members of the base class and also adds its own.

e.g: Child inherits features from their parents refine some of them and add a few of their own.

6.What is Object-Based Language ?

Languages that do not support OOPS featurs like inheritance and polymorphism but only supports objects are called object-based language. e.g: Visual Basic

7.Why we use Interface ?

Interfaces provides the flexibility to change the Implemenatation with out breaking the existing clients. Interfaces are used in COM, EJB e.t.c