Python OOP: Classes and Objects

class Student:
    college = "ABC Institute"          # class attribute

    def __init__(self, name, marks):
        self.name = name                # instance attributes
        self.marks = marks

    def result(self):
        return "Pass" if self.marks >= 40 else "Fail"

s = Student("Neha", 67)
print(s.name, s.college, s.result())

class Shape:
    def area(self):
        return 0

class Rect(Shape):
    def __init__(self, l, b):
        self.l, self.b = l, b
    def area(self):
        return self.l * self.b

class Circle(Shape):
    def __init__(self, r):
        self.r = r
    def area(self):
        return round(3.14159 * self.r ** 2, 2)

for sh in [Rect(4, 5), Circle(2)]:
    print(type(sh).__name__, sh.area())   # polymorphism

class Account:
    def __init__(self):
        self.__balance = 0
    def deposit(self, amt):
        if amt > 0:
            self.__balance += amt
    @property
    def balance(self):
        return self.__balance

a = Account(); a.deposit(500)
print(a.balance)