using System;

    abstract class person

    {

        public string firstname;

        public string lastname;

        public int age;

        public string phonenumber;

        public abstract void printdetails(); // abstract method

    }

​

    class student : person

    {

        public int rollno;

        public int fees;

        public override void printdetails()  // abstract method body in child class, override the abstract method

        { 

            string name = this.firstname + " " + this.lastname;

            Console.WriteLine(" student name is : {0} " , name);

            Console.WriteLine(" student age is : {0} " , this.age);

            Console.WriteLine(" student phonenumber is :{0} " , this.phonenumber);

            Console.WriteLine(" student rollno is :{0} " , this.rollno);

            Console.WriteLine(" student fees is :{0} " , this.fees);    

    }

    }

​

​

    class teacher : person

    {

        public string qualification;

        public int salary;

        public override void printdetails()  // same method in child class

        {

            string name = this.firstname + " " + this.lastname;

            Console.WriteLine(" teacher name is : {0} " , name);

            Console.WriteLine(" teacher age is : {0} " , this.age);

            Console.WriteLine(" teacher phonenumber is :{0} " , this.phonenumber);

            Console.WriteLine(" teacher qualification is :{0} " , this.qualification);

            Console.WriteLine(" teacher salary is :{0} " , this.salary);

        }

    }

​

​

​

​

​

public class Program

{

    public static void Main()

    {

        student obj = new student();

        obj.firstname = "himani";

        obj.lastname = "chawla";

        obj.age = 24;

        obj.phonenumber = "09876523456";

        obj.rollno = 111;

        obj.fees = 4000;

        obj.printdetails();

        Console.WriteLine(" ....................");

        teacher obj1= new teacher();

        obj1.firstname = "sushil";

        obj1.lastname = " kumar";

        obj1.age = 34;

        obj1.phonenumber = "08765498765";

        obj1.qualification = " phd in computers";

        obj1.salary = 56000;

        obj1.printdetails();

    }

}