using System;

​

public class Program

{

    string[] arrDates = new string[10000];

    Int64 regexTime, tryParseTime;

    public static void Main()

    {

        var p = new Program();

        p.initialise();

        p.regexTime = p.RunRegexDemo();

        p.tryParseTime = p.RunDateTimeParseDemo();

        string.Format("Tests concluded. RegEx.IsMatch took: {0}ms, DateTime.TryParse took: {1}", p.regexTime, p.tryParseTime).Dump();

    }

​

    public void initialise()

    {

        Random ryear, rmonth, rdate;

        ryear = new Random();

        rmonth = new Random();

        rdate = new Random();

        int y, m, d;

        DateTime dt;

        for (int i = 0; i < arrDates.Length; i++)

        {

            y = 0;

            m = 0;

            d = 0;

            while (y < 1850)

            {

                y = ryear.Next(2050);

            }

​

            while (m < 1 || m > 12)

            {

                m = rmonth.Next(12);

            }

​

            while (d < 1 || d > 28)

            {

                d = rdate.Next(28);

            }

​

            dt = new DateTime(y, m, d);

            arrDates[i] = dt.ToString("yyyy-MM-dd");

        }

    }

​

    public Int64 RunRegexDemo()

    {

        System.Diagnostics.Stopwatch st = new System.Diagnostics.Stopwatch();

        Console.WriteLine("Starting Regex demo .....");

        st.Start();

        int i = 1;

        foreach (string x in arrDates)

        {

            var result = System.Text.RegularExpressions.Regex.IsMatch(x, @"^(19|20)\d\d[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])$");

            //Console.Write(result);

            //(string.Format("{0}{1}. {2} is a valid date? = {3}", System.Environment.NewLine, i++, x, System.Text.RegularExpressions.Regex.IsMatch(x, @"^(19|20)\d\d[- /.](0[1-9]|1[012])[- /.](0[1-9]|[12][0-9]|3[01])$"))).Dump();

        }

​

        st.Stop();

        ("Ended RegEx demo. Elapsed time: " + st.ElapsedMilliseconds).Dump();

        return st.ElapsedMilliseconds;

    }

​

    public Int64 RunDateTimeParseDemo()

    {

        var st = new System.Diagnostics.Stopwatch();

        Console.WriteLine("Starting DateTime.Parse demo .......");

        st.Start();

        DateTime dt;

        foreach (string x in arrDates)

        {

            var result = DateTime.TryParse(x, out dt);

        //(string.Format("{0}{1} is a valid date? = {2}", System.Environment.NewLine, x, DateTime.TryParse(x, out dt))).Dump();

        }

​

        st.Stop();

        ("Ended TryParse demo. Elapsed time: " + st.ElapsedMilliseconds).Dump();

        return st.ElapsedMilliseconds;

    }

}