using System;

using System.Threading;

using System.Diagnostics;

using System.Threading.Tasks;

public class Program

{

    public static void Main()

    {

        Console.WriteLine($"Main Thread Id: {Thread.CurrentThread.ManagedThreadId:00}");

​

        // Run threads...

        RunThreads();

        // Run tasks in multiple ways...

        RunTasks_UsingNewStartWait();

        RunTasks_UsingRunWaitAll();

        RunTasks_UsingParallelInvoke();

    }

​

    private static void RunThreads()

    {

        Thread[] threads = new Thread[10];

        var stopWatch = new Stopwatch();

        var elapsed = new TimeSpan();

​

        Console.WriteLine("\nRunning Threads...");

        // create the threads

        for (int i = 0; i < threads.GetLength(0); i++) 

        {

            int x = i;

            threads[i] = new Thread(() => Worker_ConstantWorkLoad(x + 1));

        }

        stopWatch.Start();

        // run the threads

        for (int i = 0; i < threads.GetLength(0); i++)

        {

            threads[i].Start();

        }

        // wait for the threads to finish

        for (int i = 0; i < threads.GetLength(0); i++)

        {

            threads[i].Join();

        }

        stopWatch.Stop();

        elapsed = stopWatch.Elapsed;

        Console.WriteLine($"All Threads Completed {elapsed.Milliseconds}ms");

    }

    private static void RunTasks_UsingNewStartWait()

    {

        Task[] tasks = new Task[10];    

        var stopWatch = new Stopwatch();

        var elapsed = new TimeSpan();

​

        Console.WriteLine("\nRunning Tasks Using New, Start, and Wait...");

        // create the tasks

        for (int i = 0; i < tasks.GetLength(0); i++) 

        {

            int x = i;

            tasks[i] = new Task(() => Worker_ConstantWorkLoad(x + 1));

        }

        // run the tasks

        stopWatch.Start();

        for (int i = 0; i < tasks.GetLength(0); i++) 

        {

            tasks[i].Start();

        }

        // wait for the tasks to finish

        for (int i = 0; i < tasks.GetLength(0); i++) 

        {

            tasks[i].Wait();

        }

        stopWatch.Stop();

        elapsed = stopWatch.Elapsed;

        Console.WriteLine($"All Tasks Completed {elapsed.Milliseconds}ms");

    }

​

    private static void RunTasks_UsingRunWaitAll()

    {

        Task[] tasks = new Task[10];    

        var stopWatch = new Stopwatch();

        var elapsed = new TimeSpan();

​

        Console.WriteLine("\nRunning Tasks using Run and WaitAll...");

        // create and run the tasks

        stopWatch.Start();

        for (int i = 0; i < tasks.GetLength(0); i++) 

        {

            int x = i;

            tasks[i] = Task.Run(() => Worker_ConstantWorkLoad(x + 1));

        }

        // wait for the tasks to finish

        Task.WaitAll(tasks);

        stopWatch.Stop();

        elapsed = stopWatch.Elapsed;

        Console.WriteLine($"All Tasks Completed {elapsed.Milliseconds}ms");

    }

    private static void RunTasks_UsingParallelInvoke()

    {

        Action[] tasks = new Action[10];

        var stopWatch = new Stopwatch();

        var elapsed = new TimeSpan();

​

        Console.WriteLine("\nRunning Tasks using Parallel Invoke...");

        // create the tasks

        for (int i = 0; i < tasks.GetLength(0); i++) 

        {

            int x = i;

            tasks[i] = () => Worker_ConstantWorkLoad(x + 1);

        }

        // run the tasks and wait for them to finish using Parallel.Invoke()

        stopWatch.Start();

        Parallel.Invoke(tasks);

        stopWatch.Stop();

        elapsed = stopWatch.Elapsed;

        Console.WriteLine($"All Tasks Completed {elapsed.Milliseconds}ms");

    }

​

    private static void Worker_ConstantWorkLoad(int workerId)

    {

        Console.WriteLine($"Worker {workerId:00} Thread Id {Thread.CurrentThread.ManagedThreadId:00}: Running...");

        var stopWatch = new Stopwatch();

        stopWatch.Start();

        Thread.Sleep(100); // constant workload, 100ms

        stopWatch.Stop();

        var ts = stopWatch.Elapsed;

        Console.WriteLine($"Worker {workerId:00} Thread Id {Thread.CurrentThread.ManagedThreadId:00}: Done {ts.Milliseconds}ms");

    }   

​

    private static Random random = new Random();

    private static void Worker_VariableWorkLoad(int workerId)

    {

        Console.WriteLine($"Worker {workerId:00} Thread Id {Thread.CurrentThread.ManagedThreadId:00}: Running...");

        var stopWatch = new Stopwatch();

        stopWatch.Start();

        Thread.Sleep(random.Next(1,10) * 10); // variable workload, 10-99ms 

        stopWatch.Stop();

        var ts = stopWatch.Elapsed;

        Console.WriteLine($"Worker {workerId:00} Thread Id {Thread.CurrentThread.ManagedThreadId:00}: Done {ts.Milliseconds}ms");

    }

}