// Solution for .NET Fiddle Four years after original post ... console compilation on .net Fiddle require that both the class containing the main method and the static main method have to be marked public.

// https://docs.microsoft.com/en-us/dotnet/csharp/programming-guide/concepts/async/

using System.Threading.Tasks;

using System;

using System.Collections.Generic;

​

// Here's an async fiddle that actually works in Net Fiddle, using .NET 4.7.2 compiler : https://dotnetfiddle.net/VhZdLU

​

public class Program

{

// Define the classes

private class Juice { }

private class Coffee { }

private class Egg { }

private class Toast { }

private class Bacon { }

​

    public static async Task Main()

    {

        Console.Clear();

        await Task.Delay(300);  // execution stops at these lines in Roslyn

        /*

        Coffee cup = PourCoffee();

        Console.WriteLine("coffee is ready");

        var eggsTask = FryEggsAsync(2);

        var breakfastTasks = new List<Task> { eggsTask };

        Task finishedTask = await Task.WhenAny(breakfastTasks);

        if (finishedTask == eggsTask)

        {

            Console.WriteLine("eggs are ready");

        }

        */

        Console.WriteLine("Done making breakfast");

    }

    /*

public static async Task Main(string[] args)

{

    Coffee cup = PourCoffee();

    Console.WriteLine("coffee is ready");

​

    var eggsTask = FryEggsAsync(2);

    var baconTask = FryBaconAsync(3);

    var toastTask = MakeToastWithButterAndJamAsync(2);

​

    var breakfastTasks = new List<Task> { eggsTask, baconTask, toastTask };

    while (breakfastTasks.Count > 0)

    {

        Task finishedTask = await Task.WhenAny(breakfastTasks);

        if (finishedTask == eggsTask)

        {

            Console.WriteLine("eggs are ready");

        }

        else if (finishedTask == baconTask)

        {

            Console.WriteLine("bacon is ready");

        }

        else if (finishedTask == toastTask)

        {

            Console.WriteLine("toast is ready");

        }

        breakfastTasks.Remove(finishedTask);

    }

​

    Juice oj = PourOJ();

    Console.WriteLine("oj is ready");

    Console.WriteLine("Breakfast is ready!");

}

​

static async Task<Toast> MakeToastWithButterAndJamAsync(int number)

{

    var toast = await ToastBreadAsync(number);

    ApplyButter(toast);

    ApplyJam(toast);

​

    return toast;

}

​

private static Juice PourOJ()

{

    Console.WriteLine("Pouring orange juice");

    return new Juice();

}

​

private static void ApplyJam(Toast toast) =>

    Console.WriteLine("Putting jam on the toast");

​

private static void ApplyButter(Toast toast) =>

    Console.WriteLine("Putting butter on the toast");

​

private static async Task<Toast> ToastBreadAsync(int slices)

{

    for (int slice = 0; slice < slices; slice++)

    {

        Console.WriteLine("Putting a slice of bread in the toaster");

    }

    Console.WriteLine("Start toasting...");

    await Task.Delay(3000);

    Console.WriteLine("Remove toast from toaster");

​

    return new Toast();

}

​

private static async Task<Bacon> FryBaconAsync(int slices)

{

    Console.WriteLine($"putting {slices} slices of bacon in the pan");

    Console.WriteLine("cooking first side of bacon...");

    await Task.Delay(3000);

    for (int slice = 0; slice < slices; slice++)

    {

        Console.WriteLine("flipping a slice of bacon");

    }

    Console.WriteLine("cooking the second side of bacon...");

    await Task.Delay(3000);

    Console.WriteLine("Put bacon on plate");

​

    return new Bacon();

}

*/

private static async Task<Egg> FryEggsAsync(int howMany)

{

    Console.WriteLine("Warming the egg pan...");

    await Task.Delay(3000);

    Console.WriteLine($"cracking {howMany} eggs");

    Console.WriteLine("cooking the eggs ...");

    await Task.Delay(3000);

    Console.WriteLine("Put eggs on plate");

​

    return new Egg();

}

​

private static Coffee PourCoffee()

{

    Console.WriteLine("Pouring coffee");

    return new Coffee();

}

​

}

​