OOps

What is oops concept?
-> Object-Oriented Programming is a methodology or paradigm to design a program using classes and objects.
-> It simplifies the software development and maintainance by providing some concepts:
    1. Object
    2. Class
    3. Inheritance
    4. Polymorphism
    5. Abstraction
    6. Encapsulation

Object:
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-> Instance of a class is known as an Object whereas instance is nothing but allocating sufficient amount of memory
     space for the data members of a class.
-> Any entity that has state and behavior is known as an object.
-> For example: chair, pen, table, keyboard, bike etc.
-> It can be physical and logical.

Class:
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-> The process of binding data-members and associated methods in a single unit is called class.
-> Collection of objects is nothing but class. It is logical entity.

Inheritance:
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-> When an object acquires all the properties and behaviors of parent class object.
     i.e., known as inheritance. It provides code-reusability. It is used to achieve runtime polymorphism.

Polymorphism:
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-> When one task is performed by different ways. i.e., known as polymorphism.
-> The process of representing "one form in multiple forms" whereas One form represents
     original method and it always resides in Base class. Multiple forms represent overriden
     methods and they always resides in derived class.
Ex: void sum()------>BC void sum()----->DC1 void sum()--------->DC2
       { { {
            a=10; b=20;      f1=10.5f; f2=12.5f;      c1='A'; c2='B';
            S.o.p(a+b);      S.o.p(f1+f2);      S.o.p(c1+c2);
       } } }
Ex: To convince the customer differently.
       To draw something  eg: shape or rectangle.
-> In java, we use method overloading and method overriding to achieve polymorphism.
-> Another example can be to speak something e.g. cat speaks meaw, dog barks woof etc.


Abstraction:   (Security Purpose)
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-> Highlighting set of services what we are offering and hiding implementation details is nothing but Abstraction. Example: ATM.
-> Hiding internal details and showing functionality is known as abstraction.
-> For example: phone call, we don't know the internal processing.
-> In java, we use abstract class and interface to achieve abstraction.

Encapsulation:
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-> Binding (or wrapping) code and data together into a single unit is known as encapsulation.
-> For example: capsule, it is wrapped with different medicines.
-> A java class is the example of encapsulation. Java bean is the fully encapsulated class
-> because all the data members are private here.