using System;

public class Program

{

    public static void Main()

    {

        int number =1021;

​

        // Sample for   Format string to a 3 digit number   http://stackoverflow.com/questions/12570807/format-string-to-a-3-digit-number/42921333

        Console.WriteLine("Convert whatever number to 3-digit , e.g. {0} with ",number);

        Console.WriteLine("============================ ");

        Console.WriteLine("");

        Console.WriteLine( "{0,-20} formatting:\t{1:D3}","D3",number);

        Console.WriteLine("{0,-20} formatting:\t{1:000}","000",number);

        Console.WriteLine("{0,-20} formatting:\t{1:000} // 3-digit  as Expected","000 with % 1000", number%1000);

        Console.WriteLine("{0,-20} formatting:\t{1:D3} // 3-digit as Expected","D3 with % 1000", number%1000);

        //Console.WriteLine("000 formatting:\t"+number.ToString("000"));

    }

}