Is polymorphism the same as inheritance?
In the realm of object-oriented programming (OOP), two fundamental concepts often come up in discussions: polymorphism and inheritance. Many beginners in OOP may wonder if these two concepts are the same. While they are closely related, they are not identical. This article aims to clarify the differences between polymorphism and inheritance, helping readers understand their unique roles in OOP.
Polymorphism: The Power of Many Forms
Polymorphism is a concept that allows objects of different classes to be treated as objects of a common superclass. It is derived from the Greek words “poly” (many) and “morphe” (form). In other words, polymorphism enables a single interface to represent multiple types of objects. This concept is often exemplified by the “Animal” superclass and its subclasses, such as “Dog” and “Cat.”
For instance, consider a method called “makeSound” in the “Animal” superclass. Each subclass, like “Dog” and “Cat,” can override this method to produce a unique sound. When a program calls the “makeSound” method on an object of type “Animal,” the actual sound produced depends on the object’s actual type. This is an example of polymorphism in action.
Inheritance: The Foundation of Polymorphism
Inheritance is a mechanism that allows a class to inherit properties and behaviors from another class. The class that inherits is called the subclass, and the class from which it inherits is called the superclass. Inheritance is the foundation upon which polymorphism is built.
Using the “Animal” superclass example, the “Dog” and “Cat” classes can inherit the properties and methods of the “Animal” superclass. This allows the subclasses to share common attributes and behaviors without having to redefine them. For instance, both “Dog” and “Cat” can inherit the “makeSound” method from the “Animal” superclass.
Difference Between Polymorphism and Inheritance
While polymorphism and inheritance are closely related, they are not the same. Here are some key differences:
1. Polymorphism is a concept that allows objects of different classes to be treated as objects of a common superclass. Inheritance is a mechanism that enables a class to inherit properties and behaviors from another class.
2. Polymorphism is the result of inheritance. In other words, without inheritance, there would be no polymorphism.
3. Polymorphism is about behavior, while inheritance is about structure. Polymorphism allows objects to exhibit different behaviors based on their actual type, while inheritance allows classes to share common properties and behaviors.
4. Polymorphism can exist without inheritance. For example, in functional programming, polymorphism can be achieved through higher-order functions and type classes.
Conclusion
In conclusion, while polymorphism and inheritance are closely related, they are not the same. Polymorphism is a powerful concept that allows objects of different classes to be treated as objects of a common superclass, while inheritance is the mechanism that enables this polymorphism. Understanding the differences between these two concepts is crucial for mastering object-oriented programming.
