class TestRegularExpressions
{
    static void Main()
    {
        string[] sentences = 
        {
            "cow over the moon",
            "Betsy the Cow",
            "cowering in the corner",
            "no match here"
        };

        string sPattern = "cow";

        foreach (string s in sentences)
        {
            System.Console.Write("{0,24}", s);

            if (System.Text.RegularExpressions.Regex.IsMatch(s, sPattern, System.Text.RegularExpressions.RegexOptions.IgnoreCase))
            {
                System.Console.WriteLine("  (match for '{0}' found)", sPattern);
            }
            else
            {
                System.Console.WriteLine();
            }
        }

        // Keep the console window open in debug mode.
        System.Console.WriteLine("Press any key to exit.");
        System.Console.ReadKey();

    }
}
/* Output:
           cow over the moon  (match for 'cow' found)
           Betsy the Cow  (match for 'cow' found)
           cowering in the corner  (match for 'cow' found)
           no match here
*/

class TestRegularExpressionValidation
{
    static void Main()
    {
        string[] numbers = 
        {
            "123-456-7890", 
            "444-234-22450", 
            "690-203-6578", 
            "146-893-232",
            "146-839-2322",
            "4007-295-1111", 
            "407-295-1111", 
            "407-2-5555", 
        };

        string sPattern = "^\\d{3}-\\d{3}-\\d{4}$";

        foreach (string s in numbers)
        {
            System.Console.Write("{0,14}", s);

            if (System.Text.RegularExpressions.Regex.IsMatch(s, sPattern))
            {
                System.Console.WriteLine(" - valid");
            }
            else
            {
                System.Console.WriteLine(" - invalid");
            }
        }

        // Keep the console window open in debug mode.
        System.Console.WriteLine("Press any key to exit.");
        System.Console.ReadKey();
    }
}
/* Output:
      123-456-7890 - valid
     444-234-22450 - invalid
      690-203-6578 - valid
       146-893-232 - invalid
      146-839-2322 - valid
     4007-295-1111 - invalid
      407-295-1111 - valid
        407-2-5555 - invalid
*/