ExtractEmails

using System;
using System.Collections.Generic;
using System.Linq;
using System.Text;
using System.Text.RegularExpressions;

class ExtractEmails
{
    static void Main()
    {
        string input = @"Please contact us by phone (+359 222 222 222) or
                        by email at exa_mple@abv.bg or at baj.ivan@yahoo.co.uk.
                        This is not email: test@test. This also: @telerik.com. Neither this: a@a.b.";
        string[] splitted = input.Split(' ');

        for (int i = 0; i < splitted.Length; i++)
        {
            if (Regex.IsMatch(splitted[i], @"[\w.]{2,20}@[\w]{2,20}[.]{1}[\w.]{2,6}"))
            {
                Console.WriteLine("{0} is a valid email", splitted[i]);
            }
        }
    }
}