practice6.py

# Book Polymorphism

# Implement a class called Book with the following:

# A constructor that takes 3 parameters and initializes three instance properties: title, author, and year.
# An instance method called description that returns the following formatted string: "{title} is written by {author} and was published in {year}.".

# Implement a second class called NonfictionBook that inherits from the Book class and implements the following methods:

# A constructor that takes 4 parameters and uses super() to reuse the Book class constructor method to initialize the instance properties title, author, and year. The constructor should also initialize a fourth instance property called subject.
# An instance method called description that will override the parent class Book's method of the same name. For the NonfictionBook class, this method should return the following formatted string: "{title} is written by {author} and was published in {year}. It is a nonfiction book about {subject}."

# Write your class here.

class Book:
  def __init__(self, title, author, year):
    self.title = title
    self.author = author
    self.year = year

  def description(self):
    return f"{self.title} is written by {self.author} and was published in {self.year}."


class NonfictionBook(Book):
  def __init__(self, title, author, year, subject):
    super().__init__(title, author, year)
    self.subject = subject

  def description(self):
    return f"{self.title} is written by {self.author} and was published in {self.year}. It is a nonfiction book about {self.subject}."


book = Book("Alice in Wonderland", "Lewis Carroll", 1865)
print(book.description()) # Alice in Wonderland is written by Lewis Carroll and was published in 1865.

nonfiction = NonfictionBook("Cosmos", "Carl Sagan", 1980, "cosmic evolution and human civilization")
print(nonfiction.description()) # Cosmos is written by Carl Sagan and was published in 1980. It is a nonfiction book about cosmic evolution and human civilization.