using System;

 public class Person

{

        // Field

        public string name;

​

        // Constructor that takes no arguments.

        public Person()

        {

            name = "unknown";

        }

​

        // Constructor that takes one argument.

        public Person(string nm)

        {

            name = nm;

        }

​

        // Method

        public void SetName(string newName)

        {

            name = newName;

        }

    }

​

public class TestPerson

  {

        public static void Main()

        {

            // Call the constructor that has no parameters.

            Person person1 = new Person();

            Console.WriteLine(person1.name);

​

            person1.SetName("John Smith");

            Console.WriteLine(person1.name);

​

            // Call the constructor that has one parameter.

            Person person2 = new Person("Sarah Jones");

            Console.WriteLine(person2.name);

        }

    }