Types of inheritance in C#

Inheritance is used in C# to allow one class to reuse the properties and methods of another class.

Types of Inheritance :

1. Single Inheritance – A derived class inherits from one base class.

2. Multilevel Inheritance – A class inherits from another derived class, forming a chain of inheritance.

3. Hierarchical Inheritance – Multiple classes inherit from the same base class.

4. Multiple Inheritance – A class inherits from multiple base classes; C# does not support this with classes, but it can be achieved using interfaces.

5. Hybrid Inheritance – A combination of two or more inheritance types, typically implemented in C# using interfaces.

In C#, inheritance is a mechanism where a derived class can reuse and extend the members of a base class. The main types of inheritance are:

1. Single Inheritance – One derived class inherits from one base class.

2. Multilevel Inheritance – A class inherits from another derived class, forming a chain such as Animal ? Dog ? Puppy.

3. Hierarchical Inheritance – Multiple derived classes inherit from the same base class, such as Dog and Cat inheriting from Animal.

4. Multiple Inheritance – C# does not support multiple inheritance through classes, meaning a class cannot inherit from two classes. However, a class can implement multiple interfaces.

5. Hybrid Inheritance – A combination of different inheritance types. C# doesn't support hybrid inheritance through multiple classes, but similar designs can be achieved using classes together with interfaces.

For example:

class Animal
{
    public void Eat() { }
}

class Dog : Animal
{
    public void Bark() { }
}

class Puppy : Dog
{
    public void Play() { }
}

Here, Dog demonstrates single inheritance and Puppy demonstrates multilevel inheritance.

One important point is that C# supports multiple interface implementation but not multiple class inheritance, which helps avoid ambiguity and the "diamond problem."

Types of Inheritance in C#

C# supports five types of inheritance conceptually, though not all of them are supported directly through classes — some need interfaces to work around C#'s "no multiple class inheritance" rule.

1. Single Inheritance

One class inherits from exactly one base class. This is the simplest and most common form.

public class Beverage
{
    public void Prepare() => Console.WriteLine("Preparing beverage");
}

public class Coffee : Beverage
{
    public void Brew() => Console.WriteLine("Brewing coffee");
}

Coffee has access to everything in Beverage, plus its own members.

2. Multilevel Inheritance

A chain — a class inherits from a derived class, which itself inherited from another base class.

public class Beverage { public void Prepare() { } }
public class Coffee : Beverage { public void Brew() { } }
public class Latte : Coffee { public void AddMilk() { } }

Latte inherits from Coffee, which inherits from Beverage — so Latte gets members from both ancestors.

3. Hierarchical Inheritance

Multiple classes inherit from the same single base class.

public class Beverage { public void Prepare() { } }
public class Coffee : Beverage { }
public class Tea : Beverage { }
public class Juice : Beverage { }

Both Coffee and Tea share the common Beverage base but are unrelated to each other.

4. Multiple Inheritance (via Interfaces only)

C# does not allow a class to inherit from more than one class — this avoids the classic "diamond problem." But a class can implement multiple interfaces, which is how C# achieves multiple inheritance of behavior/contract.

public interface IPreparable { void Prepare(); }
public interface IServable { void Serve(); }

public class Coffee : IPreparable, IServable
{
    public void Prepare() => Console.WriteLine("Preparing coffee");
    public void Serve() => Console.WriteLine("Serving coffee");
}

5. Hybrid Inheritance

A combination of two or more of the above types — typically achieved in C# by mixing class inheritance with interfaces, since multiple class inheritance itself isn't available.

public class Beverage { public void Prepare() { } }
public interface IServable { void Serve(); }

public class Coffee : Beverage, IServable
{
    public void Serve() => Console.WriteLine("Serving coffee");
}

Types of inheritance in C# Single, Multilevel, and Hierarchical inheritance directly through classes. Multiple and Hybrid inheritance are implemented using interfaces