Object-oriented programming is a popular programming method used in software development. Its main building blocks are classes and objects. Classes are the blueprints that define attributes (data) and methods (functions or actions that need to be performed on the data). Objects are instances of classes but can he different attributes and use the same methods from classes.
However, classes and objects alone will not help a program run as the developer desires. To make this happen, we need to understand and apply the core principles to execute different functionalities and ensure a program in an OOP language works according to project requirements. The 4 core principles of OOP are:
Polymorphism Encapsulation Inheritance AbstractionThese 4 principles make it easier to create flexible and scalable software solutions in object-oriented programming, but this article mainly focuses on the importance of polymorphism in OOP.
Definition of Polymorphism in Object-Oriented Programming
The word “polymorphism” is derived from the Greek words “poly,” meaning “many,” and “morph,” meaning “form.” Polymorphism allows objects of different types to be treated as objects of a common type. This enables a single function or interface to work with various data types and objects, making the code easier to write, understand, and maintain.
To understand polymorphism better, let’s consider a real-life example of polymorphism in object-oriented programming. Consider an individual who is a teacher, a parent, and a friend. While the person is the same, they will adapt their behior and actions according to the scenario or situation they are in. Similarly, in OOP, polymorphism allows the same method or function to behe differently based on the object it’s interacting with.
Check out an object-oriented programming polymorphism example:
Rather than creating unique methods for each object of the class Shape, such as Circle, Square, and Triangle, a single method draw() can handle all of them, as long as they share a common interface.
Polymorphism also offers scalability to the program. As new types of objects or classes are introduced, developers can easily integrate them without modifying the existing code. This is possible because the core functionality remains the same, and only the specific behiors of the new objects are added. This minimizes the risk of potential bugs and code duplication in the program.
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Understanding the Types of Polymorphism in OOP
Polymorphism has 2 types. Developers can utilize them in their programs according to the required method behior and reusability needs. Let’s check them in detail.
1- Compile-time Polymorphism (Static Polymorphism)
Compile-time polymorphism happens when the method to be called is determined during the compilation of the code, i.e., before the program runs. This is done through method overloading and operator overloading.
Method overloading means a class has multiple methods with the same name but different parameters. Here, the compiler decides which method to use based on the number, type, or order of parameters. This helps the same method perform different actions based on the input data.
For example, consider a class with several methods named makeSound(). One version of the method plays a beep sound when called, while another version plays a melody when triggered. This enables the program to perform different actions with the same method name, making the code more organized and easier to understand.
Operator overloading lets you change how operators (like +, -, etc.) behe with custom objects, allowing them to perform different actions based on the object types.
For example, the ‘*’ operator can be overloaded to perform different tasks, such as multiplying numbers or repeating elements in an array.
Here, 4 * 7 will result in 28, while [“apple”, “banana”] * 2 will result in [“apple”, “banana”, “apple”, “banana”].
2- Runtime Polymorphism (Dynamic Polymorphism)
Runtime polymorphism happens when the method to be executed is determined during runtime, not at compile time. It is usually achieved through method overriding in object-oriented programming.
Method overriding happens when the subclass provides a specific method implementation that has already been defined in the parent class. Even though the method has the same name and signature in both the parent class and subclass, the subclass version of the method will be executed.
For example, imagine you he a superclass called Shape with a method draw(). The Circle subclass can override the draw() method to provide a specific implementation for drawing a circle, while the Square subclass can override the same method to draw a square instead.
Late Binding and Early Binding
Early binding (also called static binding) happens when the method to be invoked is resolved at compile time. This occurs in cases like method overloading, where the method signature is already known to the compiler.
Late binding (or dynamic binding) happens during runtime, which is characteristic of method overriding in runtime polymorphism. In this case, the actual method that gets called depends on the object’s type, not the reference type, providing more flexibility.
Key Misconceptions About Polymorphism
Since polymorphism is inevitable in OOP, some misconceptions around it need to be cleared.
1- Polymorphism and Inheritance are the same
There is a chance that people get confused between polymorphism and inheritance. Even though these two concepts need to work together in a program, they are completely different in terms of their purposes. Inheritance is used to inherit the attributes and methods defined in a class (parent class/superclass) to another class (child class/subclass). Here, a hierarchical connection between classes is established.
While inheritance deals with class relationships, polymorphism is about object behior flexibility. They complement each other but are distinct principles in OOP.
2- Polymorphism Reduces Performance
Another common belief is that polymorphism, particularly runtime polymorphism, significantly impacts the performance of a program. This misconception arises because runtime polymorphism often involves additional computations during program execution. However, this effect is minimal and does not significantly slow down modern applications.
Modern compilers are designed to handle runtime polymorphism efficiently. They utilize various optimization techniques, such as method dispatch tables and vtables (virtual tables), to ensure that runtime method calls are resolved quickly and with minimal performance impact. Runtime polymorphism provides more advantages, such as code reusability and flexibility in the program. Therefore, developers should not hesitate to use polymorphism just because of a small performance concern.
Polymorphism vs. Other Pillar OOP Concepts – Inheritance, Encapsulation, and Abstraction
Each concept has its own purpose in object-oriented programming. Understanding them in detail and how they differ from each other will help you use them appropriately in a program. Below, we’ll compare these concepts to highlight their distinctive benefits.
Concept Definition Key Benefit Polymorphism The ability of a function to act differently based on the input or object type. Flexibility and dynamic behior, as the same method can behe differently based on the object it operates on. Inheritance The mechanism by which one class can inherit properties and methods from another. Code reuse and creating hierarchical relationships between classes. Encapsulation The bundling of attributes and methods that operate on the attribute values into a single unit. Data protection and integrity by restricting direct access to an object’s data. Abstraction The concept of hiding the complex implementation details and showing only the essential features of an object. Simplifies complexity by providing a clear interface while hiding unnecessary details.
Conclusion
Polymorphism is one of the core concepts that keeps a program more efficient with less coding and duplication, and more flexibility. The right use of polymorphism, along with other core concepts such as inheritance, encapsulation, and abstraction, will help developers build a robust and scalable system on an object-oriented programming platform.
FAQs 1- What is polymorphism in object-oriented programming?
Polymorphism allows the same method or function to behe differently based on the object it’s acting on. It helps simplify code and makes it easier to reuse and maintain.
2- What are the types of polymorphism in OOP?
There are two main types:
Compile-time (Static) – Achieved through method or operator overloading.
Runtime (Dynamic) – Achieved through method overriding during program execution.
3- Is polymorphism the same as inheritance?
No. Inheritance lets one class use properties of another, while polymorphism allows methods to behe differently based on the object type.
4- Does polymorphism affect performance?
Not significantly. While runtime polymorphism adds minor overhead, modern compilers optimize it well. The flexibility and reusability it brings usually outweigh any performance concerns.