Inheritance basics

C# course · Intermediate · Lesson 13/116

Learn to inherit from a base class with the : operator.

Inheritance basics

Inheritance is when a class reuses another class's members. In C# it is written with a colon (:): class Dog : Animal { ... }.

Here Animal is the base class, Dog is the derived class. Dog automatically gains the public and protected members of Animal. This reduces code duplication: you write shared behavior once and reuse it across subtypes.

Base and derived class

The base class holds shared properties and methods; the derived class adds its own specific members. For example, if Animal has Name and Eat, Dog adds Bark.

C# supports single inheritance: a class can inherit from only one base class. If you need two, use interfaces. The derived class cannot call the base constructor directly; it chains with the base keyword.

Exercise Define Animal and Dog classes

Define an Animal base class with a public string Name { get; set; } property. Then declare a derived class Dog : Animal with a public void Bark() method (body: Console.WriteLine("Woof");). Inside Main create a new Dog(), set Name = "Rex", print Name and call Bark().

Show example solution

Animal and add Bark. In Main write Dog d = new Dog(); d.Name = "Rex"; Console.WriteLine(d.Name); d.Bark();
Example solution:
using System;

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

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

class Program
{
    static void Main()
    {
        Dog d = new Dog();
        d.Name = "Rex";
        Console.WriteLine(d.Name);
        d.Bark();
    }
}

Test yourself

Which is an inheritance declaration?
- class Dog : Animal { }
- class Dog extends Animal { }
- class Dog -> Animal { }
- class Dog ( Animal ) { }
Show answer

class Dog : Animal { } — Correct. In C# inheritance is written with a colon.

Complete the inheritance declaration

class Dog ____ Animal { }

Show answer

class Dog : Animal { }

Match each term to its role

Animal

Base class
Dog

Derived class
:

Inheritance operator
Bark

Method specific to Dog

Inheritance basics