What is OOPS?
OOPS stands for Object
Oriented Programming system
In OOPS the programs are
considered as a collection of objects.
Each object is nothing
but an instance of a class.
Write
basic concepts of OOPS?
Following are the concepts of OOPS and are as
follows:
Abstraction.
Encapsulation.
Inheritance.
Polymorphism.
What is a class?
A class is a collection of objects.
A class is a collection of data members, member functions, properties and
object.
It is the blueprint that describes the details of an object.
Declaration of class
Class classname
{
//variables or data members
//properties
//methods or member functions
};
Where class is a keyword and class name is userdefined that
means you can give any name to class
Example:
Class A
{
//
};
What is an object?
Object is an instance of a class, and it has its own state,
behavior and identity.
Example: if computer is a class then keyboard, mouse are the
objects.
Declaration of object:
classname referencename;
classname referencename;
Example:
A a1; //A is class name, a1 is
reference name
a1.show ();
// call or invoke the member functions to execute the program (a1 is
the reference name and show () is member function)
a1.x=5;
// used to initialize the variable (a1 is the reference name and
x is the data member )
Uses of object:
It is used to call or invoke the member functions to execute the
program.
It is used to initialize the data members.
What is Encapsulation?
Encapsulation means wrapping or hiding of data in a class and
controlling its access.
Encapsulation is implemented using private, package-private and protected access modifier.
For Example: Mobiles and owners...
all the functions of mobiles are encapsulated with the owners.
No one else can access it.
all the functions of mobiles are encapsulated with the owners.
No one else can access it.
Advantages: Security
What
is Polymorphism?
Polymorphism is nothing but assigning behavior or value in a
child class to something that was already declared in the parent class.
Polymorphism takes more than one form.
What is Inheritance?
Inheritance is a concept where one class shares the structure and behavior defined in another class.
If inheritance applied on one class is called
Single Inheritance, and if it depends on multiple classes, then it is called
multiple Inheritance.
Advantages: reusability,
extensibility.
What is
abstraction in java?
Abstraction means providing
important or necessary features without giving internal or background details.
For Example: - When user is
using Mobile application he doesn't know internal working of all functions like
calling, send Sms but he can call or send sms without knowing internal details. His main aim is using the mobile phone not to know about internal structure
What are the advantages of OOPS concepts?
Simplicity: OOPS
programming objects model real world objects, so the complexity is reduced (you
know that object is real time entity so it’s very simple to use).
Extensibility:
Adding new features or responding to changing operating environments can be
solved by introducing a few new objects and modifying some existing ones
(Inheritance).
Security: it supports encapsulation
so security level is very high
Reusability: Objects
can be reused in different programs using inheritance
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