Singleton Design Pattern

Question

Hey, can somebody give me an example of singleton design pattern? Much apriciated...

Answer 1

I think, you're looking for something like this..

    internal class Program
    {
        static TableServers host1List = TableServers.GetTableServers();
        static TableServers host2List = TableServers.GetTableServers();

        static void Main(string[] args)
        {
            TableServers servers = TableServers.GetTableServers();

            for (int i = 0; i < 5; i++)
            {
                Host1GetNextServer();
                Host2GetNextServer();
            }

            Console.ReadKey();
        }

        private static void Host1GetNextServer()
        {
            Console.Write("Next server is: ");
            Console.WriteLine(host1List.GetNextServer());
        }

        private static void Host2GetNextServer()
        {
            Console.Write("Next server is: ");
            Console.WriteLine(host2List.GetNextServer());
        }
    }

    // singleton class
    internal class TableServers
    {
        // singleton must have private readonly instance
        private static readonly TableServers _instance = new();
        private List<string> servers = new();
        public int nextServer = 0;

        private TableServers()
        {
            servers.Add("Hozna");
            servers.Add("Pepa");
            servers.Add("Jana");
            servers.Add("Kate");
        }

        // this method returns the instance
        public static TableServers GetTableServers()
        {
            return _instance;
        }

        public string GetNextServer()
        {
            string result = servers[nextServer];

            nextServer += 1;

            if (nextServer >= servers.Count)
            {
                nextServer = 0;
            }
            return result;
        }
    }