using System;
using System.Linq;
using System.Text.RegularExpressions;

public class Test
{
	public static void Main()
	{
        string sample = " class0 .calss1 .class2 .class3.class4 .class5 class6 .class7";
        Regex regex = new Regex(@"\.[^ .]+");
        var matches = regex.Matches(sample);
        string[] result = matches.Cast<Match>().Select(x => x.Value).ToArray();
        foreach (string word in result)
        {
            Console.WriteLine(word);
        }
	}
}