Inheritance

Inheritance is a mechanism where a new class (derived class or subclass) inherits attributes and methods from an existing class (base class or superclass). This allows you to create a hierarchy of classes that share common functionality while allowing specialization.

Understanding Inheritance

Inheritance creates an “is-a” relationship. For example:

• A Car is-a Vehicle
• A Dog is-an Animal
• A Manager is-an Employee

Basic Inheritance

classDiagram
    class Vehicle {
        +brand: str
        +model: str
        +year: int
        +start() str
        +stop() str
        +get_info() str
    }
    
    class Car {
        +num_doors: int
        +honk() str
    }
    
    class Motorcycle {
        +bike_type: str
        +wheelie() str
    }
    
    Vehicle <|-- Car
    Vehicle <|-- Motorcycle

Method Overriding

Subclasses can override parent methods to provide specialized behavior:

Using super()

super() Best Practice

The super() function (Python) or super keyword (Java) allows you to call methods from the parent class. Always use super()/super instead of calling the parent class directly - it handles inheritance correctly!

The super() function/keyword allows you to call methods from the parent class:

Real-World Example: E-commerce System

Multiple Inheritance

Method Resolution Order (MRO)

Key Takeaways

• Inheritance creates an “is-a” relationship between classes
• Subclasses inherit all attributes and methods from parent classes
• Method overriding allows subclasses to provide specialized behavior
• super() is used to call parent class methods
• Multiple inheritance allows a class to inherit from multiple parents
• MRO determines the order in which methods are resolved in multiple inheritance
• Use inheritance to reuse code and create specialized classes from general ones

Inheritance is powerful for creating class hierarchies where specialized classes extend and customize the behavior of more general classes.