Final answer:
The difference between implementing an interface and extending a class lies in methods and inheritance. Implementing an interface obliges a class to define specific methods per the interface's contract. Extending a class allows inheriting and possibly customizing its methods and properties.
Step-by-step explanation:
Difference Between Implementing an Interface and Extending a Class
When it comes to object-oriented programming, the concepts of implementing an interface and extending a class are fundamental. Implementing an interface means that a class agrees to perform specific actions by providing method definitions for all of the methods outlined in the interface. Conversely, extending a class means creating a subclass that inherits the properties and methods of the parent class, potentially overriding some methods and adding new properties or methods unique to the subclass.
The main difference between the two is that an interface is a contract that guarantees that a class will have certain methods, while a class is a blueprint for creating objects, which can be extended to create a more specific object with additional features or altered behavior. Notably, a class can implement multiple interfaces but can only extend one class due to the single inheritance principle in many programming languages.
For example, if we have an interface Vehicle with methods like start and stop, any class like Car or Bike implementing this interface must provide the actual implementation of these methods. On the other hand, if we have a class Vehicle with a defined set of methods and properties, a subclass like Car can extend the Vehicle class to inherit and perhaps customize this functionality.