In object-oriented programming (OOP), the concept of inheritance helps us represent the "is a" relationship between objects. This means that one object is a specialized version of another object. Let's look at some real-world examples:

• A car is a vehicle.
• A rose is a flower.
• A circle is a shape.
• A tree is a plant.

When an "is a" relationship exists, the specialized object (like a rose) has all the characteristics of the general object (like a flower) plus some additional characteristics that make it special.

Example:

Let’s create a Car superclass and two subclasses: RV and Truck. The Car class will have common attributes, while RV and Truck will have additional unique attributes.

Superclass: Car

• Attributes: make, model, and year are common to all cars.
• Method: print_info() prints out information about the car.

Subclass 1: RV

• Inheritance: By using class RV(Car):, we declare that RV is a subclass of Car.
• Calling the Superclass Constructor: super().__init__(make, model, year) initializes the common attributes.
• New Attribute: rv_type is a new attribute unique to RV.
• Overriding a Method: print_info() is redefined in RV to include rv_type.

Subclass 2: Truck

• Inheritance: By using class Truck(Car):, we declare that Truck is a subclass of Car.
• Calling the Superclass Constructor: super().__init__(make, model, year) initializes the common attributes.
• New Attribute: capacity is a new attribute unique to Truck.
• Overriding a Method: print_info() is redefined in Truck to include capacity.

Creating Objects and Using Inherited Methods

Let’s create objects of RV and Truck and see how inheritance works:

• Creating and Using an RV Object

• Creating and Using a Truck Object

 

Key Points

• Superclass and Subclass: Car is the superclass, and RV and Truck are subclasses.
• Inheritance: Both RV and Truck inherit attributes and methods from Car.
• Constructor Call: super().__init__(make, model, year) ensures that the Car constructor is called.
• Method Overriding: The print_info() method in both RV and Truck overrides the method in Car.