using System;

using System.Text;

public class Program

{

    public static void Main()

    {

        var sb = new StringBuilder();

        Console.WriteLine("Newly initialized string builder");

        if(sb.ToString() == null)

            Console.WriteLine(" Null = true");

        if(string.IsNullOrEmpty(sb.ToString()))

           Console.WriteLine("  IsNullOrEmpty = true");

        if(string.IsNullOrWhiteSpace(sb.ToString().Trim()))

           Console.WriteLine("  IsNullOrWhiteSpace = true");

        sb.Append("Hello Nisha");

        Console.WriteLine(string.Format("sb.ToString() = '{0}'", sb.ToString()));

        string myNullString = null;

        sb.AppendLine(myNullString);

        Console.WriteLine(string.Format("sb.ToString() = '{0}'", sb.ToString()));

    }

}