Python Inheritance and Method Overriding

What is Inheritance in Python?

Inheritance is an Object-Oriented Programming (OOP) feature that allows a class (child/derived class) to inherit properties and methods from another class (parent/base class). It promotes code reusability and modularity.

Syntax of Inheritance in Python:

class ParentClass:
    # parent class code

class ChildClass(ParentClass):
    # child class code

Example 1: Basic Inheritance

class Animal:
    def speak(self):
        print("Animal speaks")

class Dog(Animal):
    def bark(self):
        print("Dog barks")

# Creating object of child class
d = Dog()
d.speak()  # Inherited from Animal
d.bark()   # Defined in Dog

Output:

Animal speaks  
Dog barks

Types of Inheritance in Python

• Single Inheritance - One child, one parent
• Multiple Inheritance - One child inherits from multiple parents
• Multilevel Inheritance - Inheritance through multiple levels
• Hierarchical Inheritance - One parent, many children
• Hybrid Inheritance - Combination of multiple types

Example 2: Multilevel Inheritance

class A:
    def showA(self):
        print("This is class A")

class B(A):
    def showB(self):
        print("This is class B")

class C(B):
    def showC(self):
        print("This is class C")

obj = C()
obj.showA()
obj.showB()
obj.showC()

Output:

This is class A  
This is class B  
This is class C

What is Method Overriding in Python?

Method overriding occurs when a child class defines a method that already exists in the parent class. The child's version replaces the parent's method.

Example 3: Method Overriding

class Parent:
    def greet(self):
        print("Hello from Parent")

class Child(Parent):
    def greet(self):
        print("Hello from Child")

c = Child()
c.greet()

Output:

Hello from Child

Using super() to Access Parent Class

The super() function allows you to call the parent class methods inside the child class.

Example 4: Using super() in Overriding

class Vehicle:
    def start(self):
        print("Vehicle started")

class Car(Vehicle):
    def start(self):
        super().start()  # Call parent method
        print("Car started")

c = Car()
c.start()

Output:

Vehicle started  
Car started

Real-World Example: Inheritance and Method Overriding

class Employee:
    def work(self):
        print("Employee working...")

class Manager(Employee):
    def work(self):
        print("Manager supervising...")

e = Employee()
m = Manager()

e.work()
m.work()

Output:

Employee working...  
Manager supervising...