Inheritance_Polymorphism_Overloading_overriding.pptx

Inheritance
Polymorphism
Overloading
Overriding

What is Inheritance?
Inheritance is a powerful feature in object oriented
programming.
It is the capability of one class to derive or inherit the
properties from some another class.

Every Car is a vehicles. To show this relationship, we take an example.
Vehicles
Car
In this representation, we use an arrow towards the base class as a UML
(Unified Modeling Language) convention.

Vehicles can be called any of the following:
 Super Class
 Parent Class
 Base Class
And car is:
 Sub Class
 Child Class
 Derived Class

Inheritance Syntax
>>> class Person:
pass
>>> class Car(Vehicles):
pass
>>> issubclass(Car,Vehicles)
Here, class Car inherits from class Vehicles. We use the function
issubclass() to confirm that car is a subclass of person.

Types of Inheritance
Single
Inheritance
Multilevel
Inheritance
Multiple
Inheritance
Hierarchical
Inheritance
Hybrid
Inheritance

Single Inheritance
Child class inherits from only one parent class
Example:
class Animal:
def speak(self):
print("Animal Speaking")
#child class Lion inherits the base class Animal
class Lion(Animal):
def roar(self):
print(“Lion roaring")
d = Lion()
d.roar()
d.speak()

Lion roaring
Animal Speaking
Output:

Multiple inheritance
Inherit multiple base classes in the child class
Class 1 Class 2
Class N
Class 3

Example:
class Calculation1:
def Addition(self,x,y):
return x+y;
class Calculation2:
def Multiplication(self,x,y):
return a*b;
class Derived(Calculation1,Calculation2):
def Division(self,a,b):
return a/b;
d = Derived()
print(d.Addition(2,4))
print(d.Multiplication(2,4))
print(d.Division(2,4))

Multi-Level inheritance
Class 2
Class N
In Multi-level inheritance derived class inherits from another
derived class. There is no limit for level.
Class 1

Example:
class Animal:
def speak(self):
print("Animal Speaking")
#The child class Lion inherits the base class Animal
class Lion(Animal):
def roar(self):
print(“Lion roaring")
#The child class BabyLion inherits another child class Lion
class BabyLion(Lion):
def eat(self):
print("Eating meat...")
d = BabyLion()
d.roar()
d.speak()
d.eat()

Output:
Lion roaring
Animal Speaking
Eating meat...

Hierarchical inheritance
In hierarchical inheritance more than one derived classes are created from
a single base class.
Class 3
Class 2
Base Class
Class 1

Hybrid inheritance
Class 3
Class 4
Hybrid inheritance is a combination of multiple inheritance
and multilevel inheritance.
Class 1
Class 2

Polymorphism
 Polymorphism means many forms or multiple form.
In programming polymorphism means the same name
of function (but different parameters) that is used for
different types.
 Polymorphism simply means that we can call the
same method name with different parameters, and
depending on the parameters, it will do different
things.

Example:
len(“GKTCS")
len([5,2,8,4,45,75,3,92,33])
# returns 5 as result
# returns 9 as result
In this case the function len() taking string as input in the first case and is
taking list as input in the second case.

Overloading
Method
Overloading
Operator
Overloading
Overloading is the ability of a function or operator to behave differently dependin
g on the parameters passed on to the function or the operands on which the oper
ator operates.
Overloading

Method OR Function Overloading
Method overloading or function
overloading is a type of polymorphism in
which we can define a number of methods
with the same name but with a different
number of parameters as well as
parameters can be of different types.

Example:
# Takes two argument and print their Addition
def addition(a, b):
x = a + b
print(x)
# Takes three argument and print their Addition
def addition(a, b, c):
x = a + b + c
print(x)
# below line shows an error
#addition(7, 2)
# This line will call the second product method
addition(2, 5, 1)

Output:
 In the above code we have defined two addition method, but we can only
use the second addition method, as python does not supports method
overloading.
 We may define many method of same name and different argument but
we can only use the latest defined method. Calling the other method will
produce an error. Like here calling addition(7,2) will produce an error as
the latest defined addition method takes three arguments.
08

Operator Overloading
We can use ’+’ operator for adding numbers and at the
same time to concatenate strings. It is possible
because ’+’ operator is overloaded by both int class
and str class.

Example:
# Addition of two numbers
print(3 + 2)
# Concatenate two strings
print("GKTCS“ + “Innovations“)
# Product of two numbers
print(3 * 2)
# Repeat the String
print("GKTCS"*3)

Output:
5
GKTCS Innovations
6
GKTCSGKTCSGKTCS

Overriding
Override means having two methods with
the same name but doing different tasks.
It means that one of the methods
overrides the other.
The concept of Method overriding allows
us to change or override the Parent Class
function in the Child Class.

In Python, to override a method, you have to meet certain
conditions
 You can’t override a method within the same class. It means you
have to do it in the child class using the Inheritance concept.
 To override the Parent Class method, you have to create a method
in the Child class with the same name and the same number of
parameters.

Example:
# Python Method Overriding
class Employee:
def message(self):
print('This message is from Employee Class')
class Company(Employee):
def message(self):
print('This Company class is inherited from Employee’)
emp = Employee()
emp.message()
comp = Company()
comp.message()

Output:
'This message is from Employee Class'
'This Company class is inherited from Employee'

Inheritance_Polymorphism_Overloading_overriding.pptx

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