// https://docs.microsoft.com/en-us/dotnet/api/system.collections.generic.queue-1?view=netframework-4.8

​

using System;

using System.Collections.Generic;

​

public class Example

{

    public static void Main()

    {

        var dict = new Dictionary<int, string>();

        dict[1] = "DONE";

​

        foreach (var key in dict.Keys)

        {

            Console.WriteLine(key + ": " + dict[key]);

        }

    }

}