class ThreadTest
{
    //Index i is declared as static so that both the threads have only one copy
    static int i;


    static void Main(string[] args)
    {
        Thread t = new Thread(WriteY);
        i = 0;

        //Start thread Y
        t.Start();
        //Do something on the main thread.
        for (; i < 100; i++)
        {
            if (i % 10 == 0)
            {
                //Simulate Yield() function
                Thread.Sleep(0);
                Console.WriteLine("The X thread");
            }
            Console.Write(i + ":X ");
        }
        Console.ReadKey(true);
    }

    static void WriteY()
    {
        for (; i < 100; i++)
        {
            if (i % 10 == 0)
            {
                //Simulate Yield() function
                Thread.Sleep(0);
                Console.WriteLine("The Y thread");
            }
            Console.Write(i + ":Y ");
        }
    }
}

class Test
{
    //Index i is declared as static so that both the threads have only one copy
    static int i;

    static AutoResetEvent parentEvent = new AutoResetEvent(true);
    static AutoResetEvent childEvent = new AutoResetEvent(false);

    static void Main(string[] args)
    {
        Thread t = new Thread(WriteY);

        i = 0;

        //Start thread Y
        t.Start();
        // Print X on the main thread
        parentEvent.WaitOne();
        while (i < 100)
        {
            if (i % 10 == 0)
            {
                childEvent.Set();
                parentEvent.WaitOne();
            }
            Console.Write(i + ":Y ");
            i++;
        }
        t.Join();
    }

    static void WriteY()
    {
        childEvent.WaitOne();
        while (i < 100)
        {
            if (i % 10 == 0)
            {
                parentEvent.Set();
                childEvent.WaitOne();
            }
            Console.Write(i + ":X ");
            i++;
        }
    }
}

using System.Threading;
using System;
class ThreadTest
{
    //Index i is declared as static so that both the threads have only one copy
    static int i;

    //The lock object
    static readonly object locker = new object();

    static void Main(string[] args)
    {
        Thread t = new Thread(WriteY);

        i = 0;

        //Start thread Y
        t.Start();
        lock (locker)
        {
            // Print X on the main thread
            for (; i < 100; i++)
            {
                if (i % 10 == 0)
                {
                    Monitor.PulseAll(locker); // move any "waiting" threads to the "ready" queue
                    Monitor.Wait(locker); // relinquish the lock, and wait for a pulse
                    Console.WriteLine("The X thread");
                }
                Console.Write(i + ":X ");
            }
            Monitor.PulseAll(locker);
        }
        Console.ReadKey(true);
    }

    static void WriteY()
    {
        lock (locker)
        {
            for (; i < 100; i++)
            {
                if (i % 10 == 0)
                {
                    Monitor.PulseAll(locker); // move any "waiting" threads to the "ready" queue
                    Monitor.Wait(locker); // relinquish the lock, and wait for a pulse
                    Console.WriteLine("The Y thread");
                }
                Console.Write(i + ":Y ");
            }
            Monitor.PulseAll(locker); // move any "waiting" threads to the "ready" queue
        }
    }
}