Method overriding and method overloading are two fundamental concepts in object-oriented programming that are used to create more flexible and reusable code.

Method Overriding: Method overriding is a technique used in inheritance where a subclass provides a specific implementation of a method that is already defined in its superclass. This allows the subclass to change the behavior of the method without changing the method signature.

For example, suppose you have a base class called 'Animal' that has a method called 'MakeSound'. You might want to create a subclass called 'Dog' that has a different implementation of the 'MakeSound' method. To do this, you would define a 'MakeSound' method in the 'Dog' class with the same name and signature as the 'MakeSound' method in the 'Animal' class, but with a different implementation. This is known as method overriding.

Method Overloading: Method overloading is a technique used in polymorphism where a class can have multiple methods with the same name but different parameters. This allows the class to provide different implementations of the same method for different input types.

For example, suppose you have a class called 'Calculator' that has a method called 'Add' that takes two integers as input. If you want to provide a way to add three integers, you can overload the 'Add' method in the 'Calculator' class by defining a new 'Add' method with the same name, but with three input parameters instead of two.

The key difference between method overriding and method overloading is that method overriding is used to change the behavior of a method in a subclass, while method overloading is used to provide multiple ways to call a method with different input types in the same class.

In general, method overriding and method overloading are used to make code more flexible and reusable. Method overriding allows subclasses to provide their own implementation of a method, while still maintaining the same name and signature. This allows you to reuse code and avoid code duplication. Method overloading, on the other hand, allows you to provide multiple ways to call a method with different input types, which can make code easier to read and understand.

Overall, understanding the differences between method overriding and method overloading is essential for writing effective and efficient object-oriented code in C# and other programming languages. By using these techniques effectively, you can create code that is easier to maintain and extend, and that can be reused in a variety of different contexts.