Insert char at index in char array (in this case a number)

gistfile1.cs

using System;
using System.Windows.Forms;

namespace Script
{
    public class Script
	{
		public void Main()
		{
			int no = 52123456;
			char[] c = no.ToString().ToCharArray();
			char[] buffer = new char[c.Length + 1];
			for (int i = 0, ii = 0; i < c.Length; i++)
			{
				if (i == 2)
				{
					buffer[i] = '.';
				}
				else
				{
					buffer[i] = c[ii];
					ii++;
				}
			}
			String result = new String(buffer);

			MessageBox.Show(result);
		}
	}
}