C#

private void button1_Click(object sender, EventArgs e)
        {
            Thread t1 = new Thread(DoWork);
            Thread t2 = new Thread(DoWork);
            Thread t3 = new Thread(DoWork);
            Thread t4 = new Thread(DoWork);
            t1.Start("1");
            t2.Start("2");
            t3.Start("3");
            t4.Start("4");

        }

        public static void DoWork(object a)
        {
            while (true)
            {
                lock (key) {
                    while (block)
                    {
                        Monitor.Wait(key);
                        block = true;
                    
                    } 
                }
                Trace.Write(a.ToString() + "|");
            }

        }

        private void button2_Click(object sender, EventArgs e)
        {
            for (int i = 1; i < 2000; i++)
            {
            Trace.WriteLine("-");
            lock (key)
            {
                block = false;
                Monitor.PulseAll(key);
            }
            }
        }

Cruces wrote:

while (block)
{
  Monitor.Wait(key);
  block = true;
}

lock( key )
  while( !myHandler.hasAnswer(myQuestionCode) )
    Monitor.Wait( key );

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