Day12

Inheritance : Inheritance is one of the oops mechanism which allow to invoking all base class properties into child properties.

There are is creating two types relation-ship in between parents and child classes

1. IS-A(inheritance relationship)
2. Has-A(Composition relationship)

There are 3-types of inheritance.

1. Single inheritance
2. Multiple inheritance
3. Multi-level inheritance

Single inheritance : In this types of inheritance which is use parents properties invoke in child class :

Is-A(inheritance relationship)

Example Is-A(inheritance relationship):-
class Parent:
    parent_name = ""
    child_name = ""
 
    def show_parent(self):
        print(self.parent_name)
 
 
class Child(Parent):
    def show_child(self):
        print(self.child_name)
 
 
ch1 = Child()  
ch1.parent_name = "Sachin"  
ch1.child_name = "Arjuna"
ch1.show_parent()   
ch1.show_child()

Has-A (Composition-relationship)

class Book:
    def __init__(self, name,author,publication, price, genre):
        self.name=name
        self.author=author
        self.publication=publication
        self.price=price
        self.genre=genre
    def show_details(self):
        return"{} {} {} {} {}".format(self.name, self.author, self.publication,self.price, self.genre)


class Member:
    def __init__(self,name, id, address):
        self.name=name
        self.id=id
        self.address=address

class Library:
    working_hours = 24

    def __init__(self, name, location):
        self.name = name
        self.location = location

    @classmethod
    def change_time(cls, new_time):
        cls.working_hours = new_time

class Librarian:
    def __init__(self, name, gender, qualification, experience):
        self.name = name
        self.gender = gender
        self.qualification = qualification
        self.experience = experience
        self.list_of_books = []

    def find_total_books(self):
        return len(self.list_of_books)

    def open_lib(self):
        return "library opened"

    def issue_book(self, book_name):
        self.list_of_books.remove(book_name)
        return "book issued"

    def add_book(self, book_name):
        self.list_of_books.append(book_name)
        return "book added"

    def impose_fine(self):
        return "pay fine"

    def close_lib(self):
        return "library closed"

class Book:
    def __init__(self, name, author, publication, price, genre):
        self.name = name
        self.author = author
        self.publication = publication
        self.price = price
        self.genre = genre

    def show_details(self):
        return "{} {} {} {} {}".format(self.name, self.author, self.publication, self.price, self.genre)

class Member:
    def __init__(self, name, id, address):
        self.name = name
        self.id = id
        self.address = address

    def borrow_book(self):
        return "The book is borrowed"

    def return_book(self):
        return "The book is returned"

    def pay_fine(self):
        return "The fine to be paid"

sachin = Member("sachin", "#001", "bangalore")
saurabh = Member("saurabh", "#002", "bangalore")
rsagarwal = Librarian("rsagarwal", True, "3rd grade", 50)
rdsharma = Book("rdsharma", "sharmaji", "shawarma", 100, "shorma")
rsagarwal.list_of_books.append(rdsharma)
library = Library("420", "bangalore")
print("Total number of books in library", rsagarwal.find_total_books())

Super() : It provides the access to those methods of the parent class which have been overridden in a child class that inherits from it.

example:
class Square:
def __init__(self, side):
self.side = side
def area(self):
return self.side * self.side
class Cube(Square):
def area(self):
face_area = self.side * self.side
return face_area * 6
def volume(self):
face_area = self.side * self.side
return face_area * self.side