using System;

using System.Threading;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        //DetachedTask();

        //ParentWaitingForDetachedTask();

        //CreatingAttachedChildTask();

        PreventChildFromAttaching();

    }

    private static void DetachedTask() 

    {

        var parentTask = Task.Factory.StartNew(() => {

            Console.WriteLine("Parent task executing");

            var childTask = Task.Factory.StartNew(() => {

                Console.WriteLine("Child task executing");

                Thread.SpinWait(500000);

                Console.WriteLine("Child task completed");

            });

        });

        parentTask.Wait();

        Console.WriteLine("Parent task completed");

    }

    private static void ParentWaitingForDetachedTask() 

    {

        var parentTask = Task.Factory.StartNew(() => {

            Console.WriteLine("Parent task executing");

            var childTask = Task.Factory.StartNew(() => {

                Console.WriteLine("Child task executing");

                Thread.SpinWait(500000);

                Console.WriteLine("Child task completed");

                return "success";

            });

            Console.WriteLine(childTask.Result);

        });

        parentTask.Wait();

        Console.WriteLine("Parent task completed");

    }

    private static void CreatingAttachedChildTask()

    {

        var parentTask = Task.Factory.StartNew(() => {

            Console.WriteLine("Parent task executing");

            for(int i = 0; i < 10; i++)

            {

                Task.Factory.StartNew((taskNo) => {

                    Console.WriteLine($"Attached child task {taskNo}  completed");

                }, i, TaskCreationOptions.AttachedToParent);

            }

        });

        parentTask.Wait();

        Console.WriteLine("Parent task completed");

    }

    private static void PreventChildFromAttaching()

    {

        var parentTask = Task.Factory.StartNew(() => {

            Console.WriteLine("Parent task executing");

            for(int i = 0; i < 10; i++)

            {

                Task.Factory.StartNew((taskNo) => {

                    Console.WriteLine($"Attached child task {taskNo}  completed");

                }, i, TaskCreationOptions.AttachedToParent);

            }

        }, TaskCreationOptions.DenyChildAttach);

        parentTask.Wait();

        Console.WriteLine("Parent task completed");

    }

}