readonly keyword

Question

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

namespace ConsoleApplication19

{

class a

{

public int www;

readonly string ww = "rrr";

public string check;

}

class b : a

{

public b(int www, string ww)

{

www = 123;

ww = "rrr";

}

public void get()

{

Console.WriteLine("enter details");

this.check = Console.ReadLine();

}

public b()

{

///// if will not taken  in this constructor i got the some error if it given no error  why?

}

public void dis()

{

Console.WriteLine("check is a" + this.check);

}

}

class c : b

{

static void Main(string[] args)

{

a obj = new a();

}

}

}