11. How to program in C# - INHERITANCE - Beginner Tutorial

Introduction

This tutorial will guide you through the concept of inheritance in C#. Inheritance is a fundamental object-oriented programming principle that allows you to derive new classes from existing ones. This technique promotes code reuse, reduces errors, and enhances the readability of your programs.

Step 1: Understanding Inheritance

• Definition: Inheritance allows a class (known as a derived class) to inherit properties and methods from another class (called a base class).
• Benefits:
  • Reusability: Write once, use multiple times.
  • Minimizes redundancy: Changes made in the base class automatically reflect in derived classes.
  • Easier maintenance and organization of code.

Step 2: Creating a Base Class

• Define a base class which contains common properties and methods.
• Example code for a simple base class:

public class Animal
{
    public string Name { get; set; }

    public void Speak()
    {
        Console.WriteLine("Animal speaks");
    }
}

• Tips:
  • Keep the base class general to allow for maximum reuse across derived classes.

Step 3: Deriving a Class

• Create a derived class that inherits from the base class.
• Example code for deriving a class:

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

• Practical Advice:
  • The derived class can access public properties and methods of the base class.

Step 4: Utilizing Inheritance

• Instantiate the derived class and use inherited methods and properties.
• Example code to demonstrate usage:

public class Program
{
    public static void Main(string[] args)
    {
        Dog myDog = new Dog();
        myDog.Name = "Buddy";
        myDog.Speak(); // Inherited method
        myDog.Bark();  // Specific to Dog class
    }
}

• Common Pitfalls:
  • Ensure that the derived class does not override critical base class methods unless intended.
  • Be cautious with access modifiers (public, protected, private) to control visibility.

Step 5: Overriding Methods

• Sometimes, you need to change the behavior of a method in a derived class.
• Use the virtual keyword in the base class and override in the derived class.
• Example code:

public class Animal
{
    public virtual void Speak()
    {
        Console.WriteLine("Animal speaks");
    }
}

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

• Tip:
  • Use method overriding to provide specific implementations while maintaining a common interface.

Conclusion

Inheritance in C# is a powerful feature that enhances code reusability and maintainability. By understanding how to create base and derived classes, and how to override methods, you can build more efficient and organized programs.

Next Steps

• Explore interfaces and abstract classes for more advanced inheritance scenarios.
• Practice by creating your own classes and experimenting with method overriding to deepen your understanding.