OOPs (Object Oriented Programming System)
==========================================
High-level programming languages:
	C, C++, Java, Python etc.
==> classified into three types:
	1) Functional Programming Languages ==> C, C++, Python etc.
	2) Object Based Programming Languages ==> Class and object
		Ex: VB Script
	3) Object Oriented Programming Languages ==> C++,  Java, Python


In C:
	printf(), scanf(), putchar(), getchar(), fprintf(), fscanf(), malloc(), calloc()
add(a,b){
	printf(a+b);
}

Object Oriented Programming System (OOPs):
==========================================
	Principles
		Encapsulation
		Polymorphism
		Inheritance
		Abstraction

Encapsulation:
==============
	En+capsul
==> Binding/wrapping up of attributes (data members/variables) and methods (behaviors) into one unit as class is called as "Encapsulation".

Polymorphism
=============
	Poly + Morphs
	Many + ways

One thing ==> in many ways is called as "Polymorphism".
Method1 ==>sum
Method1 ==> difference

Inheritance
===========
process of creation of a new class from another class is called as "Inheritance".

class Class1

class Class2 from Class1

Abstraction
===========
process of showing the essential data and hiding the unessential data.

Ex: InsurancePolicy:
	def calculateRiskFactor() ==> hide
	def showCoverage():		
		implemented	==> show

HealthInsurance:
	def calculateRiskFactor():

VehicleInsurance:
	def calculateRiskFactor()
=====================================================
class TermPolicy:
	age = 30
	no alcohol
	no smoker
	software developer
	pay/month

	hide riskFactor()
	show TotalBenefit():
		coverage = 8/25/50
		


subclass Health
	dad's
			age ==> 55
			smoke
			no alcohol
			severity
	15lacks ==> 8lacks

subclass Wealth
	dad's
			age ==> 55
			smoke
			no alcohol
			severity
	15lacks ==> 8lacks
================================================================
Fundamentals of OOPs:
=====================
class
=====
	==> Logical Entity
	==> Blueprint/Plan
	==> Group/collection of attributes (data members/variables) and/or methods (behaviors) is called as "Class".
	==> keyword: class
		we can create a class.
	Syntax:
		class ClassName:
			data members
			methods

class MyFirstClass:
    # data members or attributes or variables
    name = "Ravi"
    age = 30
    role = "Software Developer"

Object
======
==> Physical Entity
==> it is an instance of a class
	which can be used to access the members of the class.
Syntax for object Creation:
===========================
	object-name = className()
Syntax:
	objectname.meberName

class MyFirstClass:
    # data members or attributes or variables
    name = "Ravi"
    age = 30
    role = "Software Developer"
    
# to access the data members of the class we should create an instance or object.

# creation of object/instance
mfc1 = MyFirstClass()

print("The Data members of the given class = ")
print(mfc1.name)
print(mfc1.age)
print(mfc1.role)
=========================================================
Method
======
==> When the class with more number of data members,
	to access these data members we need more complex code.
==> To simplify this we can use methods in class.

Function Vs Method:
====================
function ==> def keyword ==> named block==> use to define certain block of operations 
	==> function can always write in outside the class.
method ==> def keyword ==> named block ==> use to define certain block of operations	
	==> method can always write in class.

Syntax:
	class ClassName:
		def methodName(self): # without parameters
			definition
		def methodName(self,p1,p2,p3,..):# with parameters
			definition
		def methodName(self):
			definition
			return value

Here:
	self ==>keyword
		which describe the specified method belonging to the self class (same class).
	==> for self ==> no value assignment required.

class MyFirstClass:
    # data members or attributes or variables
    name = "Ravi"
    age = 30
    role = "Software Developer"
    # defining a method
    def displayData(self):
        print("My Personal Details are:")
        print("Name = ",self.name)
        print("Age = ",self.age)
        print("Role = ",self.role)
mfc = MyFirstClass()
mfc.displayData()
mfc1 = MyFirstClass()
mfc1.displayData()
===================================================
Constructor
============
# Parameterized Constructor
===========================
class Employee:
    # constructor can always use for data initialization only.
    # constructor can be invoked/called at the time of object creation
    def __init__(self,name,age,role,salary):
        self.name = name
        self.age = age
        self.role = role
        self.salary = salary
    def displayData(self):
        print("Name = ",self.name)
        print("Age = ",self.age)
        print("Role = ",self.role)
        print("Salary = ",self.salary)
        
emp1 = Employee("Ravi",30,"Software Developer","98765.0")

emp1.displayData()

emp2 = Employee("Ashish",35,"Tester",77654.0)
emp2.displayData()
==================================================
Default Constructor:
====================
==> Constructor without parameters is called as "Default Constructor".
==> for the class, how Python Interpreter allow to create an object for any class?
==================================================================================
Syntax:
	obj-name = ClassName()

==> at the time of creation of class,
	PVM (Python Virtual Machine/Interpreter) can add one default constructor.
because of this, the PVM can allow for the creation of an object.

class Student:
    # def __init__(self):
    #     self.name = "Rakesh"
    #     self.section = "10-A"
    #     self.grade = "A+"
    name = "Rakesh"
    section = "10-A"
    grade = "A+"
    
    def displayData(self):
        print(self.name,self.section,self.grade)

stu = Student()
stu.displayData()

Note:
====
We can allow only one constructor in class.