Inheritance and Polymorphism

Inheritance and polymorphism are two key concepts in object-oriented programming (OOP) that allow developers to create code that is flexible, reusable, and easy to maintain. In this blog post, we’ll take a closer look at both inheritance and polymorphism, and explore how they work together to create powerful OOP systems.

Inheritance Inheritance is a mechanism in OOP that allows a new class to be based on an existing class, inheriting all of its properties and methods. The existing class is referred to as the “parent” or “super” class, while the new class is referred to as the “child” or “sub” class. Inheritance allows developers to reuse code, making it more efficient and easier to maintain.

For example, imagine we have a parent class called “Vehicle,” which has properties like “make,” “model,” and “year,” as well as methods like “start,” “stop,” and “accelerate.” We can then create a child class called “Car,” which inherits all of the properties and methods of the “Vehicle” class, but also adds its own properties and methods specific to cars, like “numDoors,” “numSeats,” and “changeGear.”

To create an inheritance relationship between the parent and child class, we use the “extends” keyword in Java, or the ”:” symbol in Python. For example, in Java, we would write:

public class Vehicle {
  // properties and methods go here
}

public class Car extends Vehicle {
  // additional properties and methods go here
}

In Python, we would write:

class Vehicle:
  # properties and methods go here

class Car(Vehicle):
  # additional properties and methods go here

Polymorphism Polymorphism is another OOP concept that allows objects to take on many different forms. In other words, an object of a child class can be treated as if it were an object of the parent class. This allows for greater flexibility in coding, as developers can write code that works with multiple types of objects.

For example, imagine we have a parent class called “Animal,” which has a method called “makeSound.” We can then create child classes like “Dog,” “Cat,” and “Cow,” which all inherit the “makeSound” method from the parent class, but implement it differently to produce the appropriate sound for each animal. We can then write code that works with all types of animals, regardless of their specific type.

To achieve polymorphism, we use a technique called “method overriding,” which allows a child class to provide its own implementation of a method inherited from the parent class. For example, in Java, we could override the “makeSound” method in the “Dog” class like this:

public class Animal {
  public void makeSound() {
    System.out.println("Generic animal sound");
  }
}

public class Dog extends Animal {
@Override
  public void makeSound() {
    System.out.println("Bark!");
  }
}

In Python, we could override the “makeSound” method in the “Dog” class like this:

class Animal:
  def makeSound(self):
    print("Generic animal sound")

class Dog(Animal):
  def makeSound(self):
    print("Bark!")

Inheritance and polymorphism are two key concepts in OOP that allow developers to write code that is flexible, reusable, and easy to maintain. Inheritance allows new classes to be based on existing classes, inheriting their properties and methods. Polymorphism allows objects to take on many different forms, allowing for greater flexibility in coding. Together, these two concepts form the foundation of powerful OOP systems that are used in a wide variety of applications