Recently I was working with a project where I was in need to format a number in such a way which can apply leading zero for particular format.  So after doing such R and D I have found a great way to apply this leading zero format.

I was having need that I need to pad number in 5 digit format. So following is a table in which format I need my leading zero format.

1-> 00001

20->00020

300->00300

4000->04000

50000->5000

So in the above example you can see that 1 will become 00001 and 20 will become 00200 format so on. So to display an integer value in decimal format I have applied interger.Tostring(String) method where I have passed “Dn” as the value of the format parameter, where n represents the minimum length of the string. So if we pass 5 it will have padding up to 5 digits.

So let’s create a simple console application and see how its works. Following is a code for that.

```using System;

{
class Program
{
static void Main(string[] args)
{
int a = 1;
int b = 20;
int c = 300;
int d = 4000;
int e = 50000;

Console.WriteLine(string.Format("{0}------>{1}",a,a.ToString("D5")));
Console.WriteLine(string.Format("{0}------>{1}", b, b.ToString("D5")));
Console.WriteLine(string.Format("{0}------>{1}", c, c.ToString("D5")));
Console.WriteLine(string.Format("{0}------>{1}", d, d.ToString("D5")));
Console.WriteLine(string.Format("{0}------>{1}", e, e.ToString("D5")));