Class Inheritance

Classes can inherit from other classes. They can gain Public/Protected Variables and Functions of the parent class. The class then acts as a detailed version of the original parent class(also known as the base class). 
The code below shows the simplest of examples :

public class A
{
    //Define Parent Class
    public A() { }
}

public class B : A
{
    //Define Child Class
    public B() { }
}


In the following program we shall learn how to create & implement Base and Derived Classes. First we create a BaseClass and define the Constructor , SHoW & a function to square a given number. Next , we create a derived class and define once again the Constructor , SHoW & a function to Cube a given number but with the same name as that in the BaseClass. The code below shows how to create a derived class and inherit the functions of the BaseClass. Calling a function usually calls the DerivedClass version. But it is possible to call the BaseClass version of the function as well by prefixing the function with the BaseClass name.

class BaseClass
    {
        public BaseClass()
        {
            Console.WriteLine("BaseClass Constructor Called\n");
        }

        public void Function()
        {
            Console.WriteLine("BaseClass Function Called\n Enter A Single No.");
            int number = new int();
            number = Convert.ToInt32(Console.ReadLine());
            number = number * number;
            Console.WriteLine("Square is : " + number + "\n");
        }

        public void SHoW()
        {
            Console.WriteLine("Inside the BaseClass\n");
        }
    }



class DerivedClass : BaseClass
    {
        public DerivedClass()
        {
            Console.WriteLine("DerivedClass Constructor Called\n");
        }

        public new void Function()
        {
            Console.WriteLine("DerivedClass Function Called\n Enter A Single No.");
            int number = new int();
            number = Convert.ToInt32(Console.ReadLine());
            number = Convert.ToInt32(number) * Convert.ToInt32(number) 
            *Convert.ToInt32(number) ;
            Console.WriteLine("Cube is : " + number + "\n");
        }

        public new void SHoW()
        {
            Console.WriteLine("Inside the DerivedClass\n");
        }
    }


class Program
    {
        static void Main(string[] args)
        {
            DerivedClass dr = new DerivedClass();

            dr.Function(); //Call DerivedClass Function

            ((BaseClass)dr).Function(); //Call BaseClass Version

            dr.SHoW(); //Call DerivedClass SHoW

            ((BaseClass)dr).SHoW(); //Call BaseClass Version
           
            Console.ReadKey();
        }
    }

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