Domingo - Droid

🟢 Lesson 4

🔰 What Is OOP?

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Object-Oriented Programming (OOP) is a programming style where you organize code into objects that contain:

Data (attributes)
Functions (methods) that operate on that data

Python supports OOP using:

class → to define a blueprint
object → a real-world instance of a class

🧱 Example: Why Use OOP?

Instead of this:

pythonCopierModifiercar1_name = "Toyota"
car1_color = "Red"

Use this:

pythonCopierModifierclass Car:
    def __init__(self, name, color):
        self.name = name
        self.color = color

car1 = Car("Toyota", "Red")

✅ More organized, reusable, and scalable.

🏗️ Defining a Class

pythonCopierModifierclass Person:
    def __init__(self, name, age):
        self.name = name    # attribute
        self.age = age      # attribute

    def greet(self):        # method
        print(f"Hi, I'm {self.name} and I'm {self.age} years old.")

__init__ is the constructor (runs when object is created).
self refers to the instance (object itself).
greet() is a method.

🧍 Creating Objects

pythonCopierModifierperson1 = Person("Alice", 28)
person2 = Person("Bob", 35)

person1.greet()  # Output: Hi, I'm Alice and I'm 28 years old.
person2.greet()  # Output: Hi, I'm Bob and I'm 35 years old.

🧩 Key OOP Terms

Term	Meaning
`class`	Blueprint/template for creating objects
`object`	Instance of a class
`__init__`	Constructor method (runs when object is created)
`self`	Refers to the instance inside the class
method	Function defined in a class
attribute	Variable that belongs to an object

🧠 Exercise 1: Simple Bank Account Class

pythonCopierModifierclass BankAccount:
    def __init__(self, owner, balance=0):
        self.owner = owner
        self.balance = balance

    def deposit(self, amount):
        self.balance += amount
        print(f"{amount} deposited. New balance: {self.balance}")

    def withdraw(self, amount):
        if amount <= self.balance:
            self.balance -= amount
            print(f"{amount} withdrawn. New balance: {self.balance}")
        else:
            print("Insufficient balance!")

# Create an object and test it
account = BankAccount("Ali", 1000)
account.deposit(500)
account.withdraw(300)
account.withdraw(1500)

🧠 Exercise 2: Student Class With Grade

Create a Student class with:

name
grade
method to print pass/fail (passing if grade ≥ 10)

pythonCopierModifierclass Student:
    def __init__(self, name, grade):
        self.name = name
        self.grade = grade

    def check_pass(self):
        if self.grade >= 10:
            print(f"{self.name} has passed ✅")
        else:
            print(f"{self.name} has failed ❌")

# Test
student1 = Student("Sara", 14)
student2 = Student("Omar", 7)

student1.check_pass()
student2.check_pass()