How to find duplicate string in string list without using LINQ

using System;

using System.Collections.Generic;

using System.Linq;

using System.Text;

using System.Threading.Tasks;

 

namespace ConsoleApplication2

{

    class Program

    {

        static void Main(string[] args)

        {

            List<string> list = new List<string>();

            list.Add("111");

            list.Add("111");

            list.Add("222");

            list.Add("333");

            list.Add("333");

            list.Add("333");

            list.Add("444");

            list.Add("444");

            list.Add("555");           

            List<string> termsList = new List<string>();

            string[] numbers = list.ToArray();           

            int count = 0;

            int dupcount = 0;

            foreach (string s in numbers)

            {

                count++;

            }           

            foreach (string s in numbers)

            {

                dupcount = 0;

                for(int i=0; i<count; i++)

                {

                    string checkstrng = numbers[i];

                    if (s == checkstrng)

                    {

                        dupcount++;

                    }

                    if (dupcount > 1)

                    {

                        bool bdupchk = termsList.Contains(s);

                        if (bdupchk == false)

                        {

                            termsList.Add(s);

                        }                       

                        dupcount = 0;

                    }                   

                }

            }

            string[] terms = termsList.ToArray();

            foreach(string result in terms)

            {

                Console.WriteLine(result);               

            }

            Console.Read();

        }

    }

}

Output:

111

333

444