Object-Oriented Programming

class Car: def __init__(self, make, model, year): self.make = make self.model = model self.year = year self.miles = 0 def drive(self, miles): self.miles += miles return f"Drove {miles} miles" def get_info(self): return f"{self.year} {self.make} {self.model} ({self.miles} miles)" # Create objects (instances) toyota = Car("Toyota", "Camry", 2022) tesla = Car("Tesla", "Model 3", 2023) print(toyota.get_info()) # 2022 Toyota Camry (0 miles) print(tesla.drive(10000)) # Drove 10000 miles

class BankAccount: def __init__(self, owner, balance=0): self.owner = owner self.balance = balance def deposit(self, amount): if amount > 0: self.balance += amount return f"Deposited ${amount}" return "Invalid amount" def withdraw(self, amount): if 0 < amount <= self.balance: self.balance -= amount return f"Withdrew ${amount}" return "Insufficient funds" def get_balance(self): return f"${self.balance:.2f}" account = BankAccount("Alice", 1000) print(account.deposit(500)) # Deposited $500 print(account.withdraw(200)) # Withdrew $200 print(account.get_balance()) # $1300.00

class MathUtils: @classmethod def circle_area(cls, radius): return 3.14159 * radius ** 2 @staticmethod def is_even(n): return n % 2 == 0 print(MathUtils.circle_area(5)) # 78.54 print(MathUtils.is_even(4)) # True

class Car: def __init__(self, make, model): self.make = make self.model = model def start_engine(self): return f"{self.make} {self.model} engine started" class ElectricCar(Car): # Inherits from Car def __init__(self, make, model, battery_size): super().__init__(make, model) # Call parent __init__ self.battery_size = battery_size def charge_battery(self, hours): return f"Charged for {hours} hours" def get_range(self): return f"{self.battery_size * 4} miles range" tesla = ElectricCar("Tesla", "Model S", 100) print(tesla.start_engine()) # Inherited ✓ print(tesla.charge_battery(2)) # New method print(tesla.get_range()) # 400 miles range

class Vector2D: def __init__(self, x, y): self.x = x self.y = y def __str__(self): return f"Vector({self.x}, {self.y})" def __repr__(self): return f"Vector2D({self.x}, {self.y})" def __add__(self, other): return Vector2D(self.x + other.x, self.y + other.y) def __len__(self): import math return math.sqrt(self.x**2 + self.y**2) v1 = Vector2D(3, 4) v2 = Vector2D(1, 2) print(v1) # Vector(3, 4) print(v1 + v2) # Vector(4, 6) print(len(v1)) # 5.0 (magnitude)

class Employee: raise_amount = 1.04 # Class variable def __init__(self, first, last, pay): self.first = first self.last = last self.pay = pay self.email = f"{first}.{last}@company.com" def fullname(self): return f"{self.first} {self.last}" def apply_raise(self): self.pay *= self.raise_amount class Developer(Employee): raise_amount = 1.10 # 10% raise def __init__(self, first, last, pay, language): super().__init__(first, last, pay) self.language = language dev = Developer("John", "Doe", 50000, "Python") print(dev.email) # john.doe@company.com print(dev.fullname()) # John Doe dev.apply_raise() print(dev.pay) # 55000 (10% raise)