Checking_Date_format

using System;
using System.Text.RegularExpressions;

namespace Regular_Expression
{
    class Program
    {
        static void Main(string[] args)
        {
            string[] calender = {
                "1/02/2019",
                "01/12/1990",
                "11/12/1990",
                "00/12/1990",
                "01/12/19900",
                "99/12/1990"

            };

            for (int i = 0; i < calender.Length; i++)
            {
                string pattern = @"^(0?[1-9]|[12]\d|3[01])/(0[1-9]|1[0-2])/\d{4}$";
                bool ismatch = Regex.IsMatch(calender[i], pattern);
                Console.WriteLine(ismatch);
            }
            Console.ReadLine();
        }
    }
}