using System;

using System.Text;

​

​

public  class Program

{

    public static void Main(string[] args)

    {

        ClassA a = new ClassA();

        a.Name = "Golan";

        a.Id = 12345;

        ClassB b = new ClassB

        {

            Id = 23123,

            Name = "Maimon"

        };

        ClassC c = new ClassC

        {

            Id = 543455,

            Name = "Alon"

        };

​

        a.Display();

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

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

        b.Display();

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

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

        c.Display();

    }

}

​

​

public abstract class BaseClass

{

    public int Id {get; set;}

    public string Name {get; set;}

    public abstract void Display();

}

​

​

public class ClassA :BaseClass

{

    public override void Display()

    {

        Console.WriteLine(this.ToString());

    }

​

    public override string ToString()

    {

        return String.Format("ID : {0}  Name {1}", Id , Name);

    }

}

​

public class ClassB :BaseClass

{

    public override void Display()

    {

        Console.WriteLine(this.ToString());

    }

    public override string ToString()

    {

        StringBuilder str = new StringBuilder();

        str.AppendLine(String.Format("ID : {0}", Id));

        str.AppendLine(String.Format("Name {0}", Name));

        return str.ToString();

    }

}

​

public class ClassC :BaseClass

{

    public override void Display()

    {

        Console.WriteLine(this.ToString());

    }

    public override string ToString()

    {

        StringBuilder str = new StringBuilder();

        str.AppendLine(String.Format("ID : {0}", Id));

        str.AppendLine("****************************************");

        str.AppendLine(String.Format("Name {0}", Name));

        str.AppendLine("****************************************");

        return str.ToString();

    }

}