One of the most important concepts in object-oriented programming is inheritance. Inheritance allows us to define a class in terms of another class, which makes it easier to create and maintain an application. This also provides an opportunity to reuse the code functionality and fast implementation.

When creating a class, instead of writing completely new data members and member functions, the programmer can design that the new class should inherit the members of an existing class. This existing class is called the base class, and the new class is referred to as the derived class.

Syntax:

[Access Modifier] class ClassName : baseclassname
{
}

Inheritance can be classified to 5 types:

1.       Single Inheritance

2.       Hierarchical Inheritance

3.       Multi Level Inheritance

4.       Hybrid Inheritance

5.       Multiple Inheritance

Single Inheritance

Hierarchical Inheritance

Multi Level Inheritance

Hybrid Inheritance

 Multiple Inheritance

Example

using System;
namespaceInheritenceConsoleApplication
{
    classBaseClass
    {
        /// <summary>
        /// create a base class and a method in it
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        publicvoidadd(int x, int y)
        {
            Console.WriteLine("Addition : " +(x+y));
        }
    }
    classDerivedClass : BaseClass//inherit base class
    {
        /// <summary>
        /// create a derived class and a method in it
        /// </summary>
        /// <param name="x"></param>
        /// <param name="y"></param>
        publicvoidmultiply(int x, int y)
        {
            Console.WriteLine("Multiply ; "+(x*y));
        }
    }
    classProgram
    {
        staticvoidMain(string[] args)
        {
            DerivedClassdc = new DerivedClass(); // create a derived class object
            dc.add(21,34); // call base class method with derived class object
            dc.multiply(4,5);
        }
    }
}

Output :

Addition : 55

Multiply : 20

In this example, I have created two classes – one base class with method add() and derived class with method multiply(), derived class inherits the base class , in class program – create the derived class object and call the base class method add()  and derived class method multiply() with it and see the desired output.