Understanding Method Overloading and Method Overriding in Programming

When we talk about object-oriented programming (OOP), two important ideas to know are method overloading and method overriding. They are both related to something called polymorphism, but they work in different ways. Let’s break down what each one is and how they are different.

What is Method Overloading?

Method overloading happens when you have several methods in the same class that all have the same name but different details, like the number of inputs or the kind of inputs.

This is known as compile-time polymorphism because the computer decides which method to use when the code is being compiled, not when it’s running.

Here’s a simple example of method overloading in a math class:

class MathOperations {
    int add(int a, int b) {
        return a + b;
    }

    double add(double a, double b) {
        return a + b;
    }

    int add(int a, int b, int c) {
        return a + b + c;
    }
}

In this example, the add method has three different versions. The computer knows which one to use based on what you give it.

• If you call add(3, 4), it uses the first method.
• If you call add(3.5, 2.5), it uses the second method.

So, the choice of which method to run is made when the code is being compiled.

What is Method Overriding?

Method overriding is different because it occurs when a subclass (or child class) gives its own version of a method that already exists in its parent class (or superclass).

This is considered runtime polymorphism because the decision on which method to use happens when the program is running, based on the type of the object.

Here’s an example of method overriding:

class Animal {
    void sound() {
        System.out.println("Animal makes a sound");
    }
}

class Dog extends Animal {
    void sound() {
        System.out.println("Dog barks");
    }
}

class Cat extends Animal {
    void sound() {
        System.out.println("Cat meows");
    }
}

In this case, both Dog and Cat change how the sound method works. When the program runs, if you have an Animal that is actually a Dog or a Cat, it will use the correct method based on the actual object type.

Key Differences Between Overloading and Overriding

1. When it Works:

   • Overloading is decided when the code is compiled.
   • Overriding is decided when the program is running.

2. Number of Methods:

   • Overloading lets you have many methods with the same name in one class but different details.
   • Overriding lets you have one version of a method in a subclass that takes the place of the parent class’s method.

3. Type of Polymorphism:

   • Overloading shows compile-time polymorphism (or static polymorphism).
   • Overriding shows runtime polymorphism (or dynamic polymorphism).

Conclusion

In short, knowing the differences between method overloading and method overriding is important for understanding polymorphism in OOP.

Both methods have their own purposes.

• Method overloading makes the code easier to read and use by allowing different input options.
• Method overriding lets subclasses change or improve how inherited methods work for their specific needs.

These concepts are key to writing good software, making your code cleaner, easier to maintain, and flexible for future changes.