namespace ConsoleApplication2
{
   
    class Program
    {
         static  void abc(a ba)
        {
            ba.fun();
            ba.b = "1234143";
        }
        static void Main(string[] args)
        {
            a c= new a();
            c.b = "esafdf";
            abc(c);
            abc(c);
            Console.ReadKey();
        }
        
          
    }
    public class a
    {
        public string b;
        public a()
        {
            b = "abcde";
        }
        public void fun()
        {
            Console.WriteLine("{0}",b);
            
        }
    }

}