What is inheritance in C#?

C# is an object-oriented language that supports inheritance. It supports single class inheritance, but not multiple class inheritance.

Inheritance

Inheritance offers reusability. This means that the functions and variables already declared in one class can be reused in another class by making it a child of that class. This prevents the need for redundant code in the new class that is declared.

Keywords

Inheritance involves the use of base and derived classes.

Base class: This is the class from which the functions and variables are inherited. This is the parent class, also known as the super class.
Derived class: This is the class that inherits functions and variables from the super class. This is the child class, also known as the sub-class.

Overriding inherited class

If both the base class and the derived class have a function of the same name, the method associated with the derived class will be executed and the inherited function will be over-ridden. For this, the derived class function must have the same name, same parameters, and same return type (or sub-type) as a method in its base class.

// Inheritance in C#
using System;
namespace InheritanceApplication {
// this is the base class
	public class Educative {
		// constructor of base class
		public Educative() {
			Console.WriteLine("Base class constructor");
		}
		
		// method of the base class
		public int base_adder(int x, int y) {
			Console.WriteLine("Using method of base class:");
			int sum = x + y;
			return sum;
		}
	}
// this is the derived class
	public class Edpresso: Educative {
		// constructor of derived class
		public Edpresso() {
		Console.WriteLine("Derived class constructor");
		}
	}
	class Tester {
		static void Main(string[] args) {
		// creating object of base class
		Educative Edu = new Educative();
		// creating object of derived class
		Edpresso Edp = new Edpresso();
		// calling the method of super class using sub class object
		int added = Edp.base_adder(2,3);
		Console.WriteLine("sum = {0}", added);
		}
	}
}

Constructors

If you look at the output of the code snippet above, you will notice the following:

Base class constructor Base class constructor Derived class constructor

A constructor is a class method that is accessed automatically when an instance of a class is declared. Here, we declare an instance of the base class, and “Base class constructor” is printed.

When we declare an instance of the derived class, as it is inheriting from the base class, it will first access the base class constructor, then its own constructor. This leads to the output:
Base class constructor
Derived class constructor

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What is inheritance in C#?

Inheritance

Keywords

Overriding inherited class

Code

Constructors