Virtual method dispatch mechanism in C Sharp (C#) - Mini Project: Build & Apply

Virtual method dispatch mechanism

📖 Scenario: Imagine you are creating a simple program to show how different animals make sounds. Each animal can make a sound, but the exact sound depends on the type of animal.

🎯 Goal: You will build a small program with a base class Animal and two derived classes Dog and Cat. You will use virtual methods to show how the program decides which sound to make when calling the method on different animals.

📋 What You'll Learn

Create a base class called Animal with a virtual method MakeSound() that prints "Some sound".

Create two classes Dog and Cat that inherit from Animal and override the MakeSound() method to print "Bark" and "Meow" respectively.

Create a list of Animal objects containing one Dog and one Cat.

Use a foreach loop to call MakeSound() on each animal and print the result.

💡 Why This Matters

🌍 Real World

Virtual method dispatch is used in many programs to allow different objects to behave differently while sharing the same interface. For example, in games, different characters can move or attack differently but use the same method names.

💼 Career

Understanding virtual methods and polymorphism is essential for object-oriented programming jobs. It helps write flexible and reusable code that can handle many types of objects easily.

1

Create the base class Animal with a virtual method

Create a public class called Animal with a public virtual method MakeSound() that prints "Some sound" using Console.WriteLine.

C Sharp (C#)

// Your code here

Need a hint?

Use the virtual keyword to allow the method to be overridden in child classes.

2

Create Dog and Cat classes overriding MakeSound

Create two public classes Dog and Cat that inherit from Animal. Override the MakeSound() method in Dog to print "Bark" and in Cat to print "Meow" using Console.WriteLine.

C Sharp (C#)

using System;

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

// Your code here

Need a hint?

Use the override keyword to change the behavior of the virtual method in child classes.

3

Create a list of Animal objects with Dog and Cat

Create a List<Animal> called animals and add one Dog object and one Cat object to it. Remember to include using System.Collections.Generic; at the top.

C Sharp (C#)

using System;
using System.Collections.Generic;

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

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

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

// Your code here

Need a hint?

Use List<Animal> to hold different animal objects because they share the same base class.

4

Use foreach loop to call MakeSound on each animal

Add a foreach loop inside Main() to go through each animal in animals and call animal.MakeSound(). This will print the correct sound for each animal.

C Sharp (C#)

using System;
using System.Collections.Generic;

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

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

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

class Program
{
    static void Main()
    {
        List animals = new List();
        animals.Add(new Dog());
        animals.Add(new Cat());

        // Use foreach loop to call MakeSound on each animal
        // Your code here
    }
}

Need a hint?

The foreach loop calls the overridden MakeSound() method for each animal, showing how virtual method dispatch works.