Day 11 - Class Work

What is OOP?

Object-Oriented Programming (OOP) is a programming style that uses classes and objects to organize code. It helps in writing reusable, modular, and organized programs.

Without OOP vs With OOP

# Print details of students
print("Name: Arun, Age: 21")
print("Name: Hasvanth, Age: 22")
print("Name: Ayyappan, Age: 23")

class Student:
    def __init__(self, name, age):
        self.name = name
        self.age = age

    def display(self):
        print("Name:", self.name, ", Age:", self.age)

s1 = Student("Arun", 21)
s2 = Student("Hasvanth", 22)
s3 = Student("Ayyappan", 23)

s1.display()
s2.display()
s3.display()

Syntax of a Class and Object

class ClassName:
    def __init__(self, parameter1, parameter2):
        # constructor code
        self.parameter1 = parameter1
        self.parameter2 = parameter2

    def method_name(self):
        # method code
        print(self.parameter1, self.parameter2)

# Creating object
obj = ClassName(value1, value2)
obj.method_name()

1. Simple class with method

class Person:
    def greet(self):
        print("Hello!")

p = Person()
p.greet()
# Output:
# Hello!

2. Class with constructor (__init__)

class Person:
    def __init__(self, name):
        self.name = name

    def greet(self):
        print("Hello,", self.name)

p = Person("Arun")
p.greet()
# Output:
# Hello, Arun

3. Multiple objects

p1 = Person("Hasvanth")
p2 = Person("Ayyappan")
p1.greet()
p2.greet()
# Output:
# Hello, Hasvanth
# Hello, Ayyappan

4. Class with multiple methods

class Calculator:
    def add(self, a, b):
        print("Sum:", a+b)

    def multiply(self, a, b):
        print("Product:", a*b)

calc = Calculator()
calc.add(5, 3)
calc.multiply(5, 3)
# Output:
# Sum: 8
# Product: 15

5. Class with attributes

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

s = Student("Arun", "A")
print(s.name, s.grade)
# Output:
# Arun A