Method Overriding in C#

What is Method Overriding in C#?

Method Overriding is a feature in C# that allows a derived class to provide a specific implementation of a method that is already defined in its base class. It is a key concept of runtime polymorphism.

Key Features of Method Overriding

• Requires a base class method to be marked as virtual or abstract.
• The derived class method must have the same signature and use the override keyword.
• Supports runtime polymorphism by determining which method to call at runtime.
• Provides flexibility by allowing derived classes to customize base class behavior.

Example of Method Overriding

The following example demonstrates how method overriding works.

Example of Method Overriding:

public class Animal
{
    public virtual void MakeSound()
    {
        Console.WriteLine("Animal makes a sound.");
    }
}

public class Dog : Animal
{
    public override void MakeSound()
    {
        Console.WriteLine("Dog barks.");
    }
}

// Usage
Animal myAnimal = new Dog();
myAnimal.MakeSound();  // Output: Dog barks.
        

In this example, the MakeSound() method in the Dog class overrides the same method in the Animal class.

Method Overriding vs. Method Hiding

C# allows both method overriding and method hiding. The difference is:

Example of Method Hiding

Below is an example where a method is hidden rather than overridden:

Example of Method Hiding:

public class Animal
{
    public void MakeSound()
    {
        Console.WriteLine("Animal makes a sound.");
    }
}

public class Dog : Animal
{
    public new void MakeSound()
    {
        Console.WriteLine("Dog barks.");
    }
}

// Usage
Animal myAnimal = new Dog();
myAnimal.MakeSound();  // Output: Animal makes a sound

Dog myDog = new Dog();
myDog.MakeSound();  // Output: Dog barks.
        

In this example, the new keyword hides the MakeSound() method of the base class instead of overriding it.

Rules for Method Overriding

• The base class method must be marked as virtual or abstract.
• The overriding method in the derived class must have the same name, return type, and parameters.
• The derived class method must be marked with the override keyword.
• Method overriding supports runtime polymorphism.

Benefits of Method Overriding

• Allows a derived class to provide a custom implementation of a base class method.
• Enables runtime polymorphism for flexible and reusable code.
• Improves maintainability by promoting modular code.
• Supports OOP principles by enhancing inheritance.