Thu Dec 14 2023

Overloading vs Overriding in Object-Oriented Programming

Overloading vs Overriding in Object-Oriented Programming

Overloading and Overriding are the two very important concept of Object Oriented Programming. It's enable developers to create flexible and reusable code. But, most of the novice programmers are confused about them or they forgot the rules on when to use which one. Let's explore the key differences between these two essential concepts.

Method Overloading

Method overloading is the ability to create multiple functions of the same name with different implementations. An overloaded function will run a specific implementation that allowing one function call to perform different tasks depending on context.

In OOPs, overloading plays an important role, which lets us define multiple methods with same name inside a class only number of parameters should be different. Overloaded methods are generally used to execute the same task, but with a different set of parameters. The actual method called during runtime is resolved at compile time, which avoid runtime errors. The concept of overloading helps to avoid redundant code, eliminates complexity, and enhances runtime performance.

For instance, consider a class with a method named calculateArea. Overloading this method allows us to define versions that accept different parameters, such as calculateArea(int side), calculateArea(int length, int breadth), or calculateArea(double radius).

Method Overriding

Method overriding occurs in a class hierarchy when a subclass provides a specific implementation of a method that is already present in its superclass. It involves redefining a method in the subclass with the same signature (method name, parameters, and return type) as in the superclass.

This concept allows for polymorphism, where a subclass can have its own implementation of a method inherited from the superclass. For example, a superclass might have a method displayInfo(), which the subclass can override with its own implementation.

Whenever we extend a parent class in a child class, the child class able to access all the methods, which is called derived methods. But in some cases, if we do not want the same parent method, then we need the concept of overriding. Overriding let us implement a parent class method in a child class with the same name and parameters. It will depend on the object which version of the method will be called during runtime. If the object is a shadow of the parent class, then method of the parent class will be called, while child class object will execute the class version of the method.

The version of a method that is executed will be determined by the object that is used to invoke it. If an object of a parent class is used to invoke the method, then the version in the parent class will be executed, but if an object of the subclass is used to invoke the method, then the version in the child class will be executed. Some languages allow a programmer to prevent a method from being overridden.

C++ and C# support overriding by explicitly using the keywords 'override' and 'virtual'. Java uses the 'super' keyword to invoke the superclass method. However, C++ uses instead the base class name followed by the scope resolution operator (::).

Key Differences

1. Usage Context:

  • Overloading is used within the same class to provide multiple methods with the same name but different parameters.
  • Overriding is applied in inheritance, allowing a subclass to provide its own implementation of a method inherited from its superclass.

2. Purpose:

  • Overloading aims to provide multiple versions of a method to handle different parameter types or numbers within the same class.
  • Overriding facilitates the specialization of methods in subclasses, enabling more specific behavior while maintaining a common interface through inheritance.

3. Resolution:

  • Overloading is resolved at compile time based on the method signature (parameters and their types).
  • Overriding is resolved at runtime, determined by the object's actual type, enabling dynamic polymorphic behavior.


Understanding the distinctions between method overloading and method overriding is crucial for writing clean, maintainable, and flexible code in object-oriented programming. Method overloading allows for multiple method signatures within a class, while method overriding enables subclasses to provide their own implementations, promoting code reusability and polymorphism.

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