public class MultiThread10
{
    private int itemCount = 0;
    private object locker = new object();
    public void Run()
    {
        Thread t = new Thread(Work);
        t.Start(300);

        Thread t1 = new Thread(Work);
        t1.Start(100);
    }

    private void Work(object delay)
    {
        lock (locker)
        {
            this.itemCount++;

            Thread.Sleep((int)delay);

            Console.WriteLine($"C# 1.0 Items in cart：{itemCount}");
        }
    }
}

public class MultiThread20
{
    private int itemCount = 0;
    private object locker = new object();

    public void Run()
    {
        Thread t = new Thread(delegate (object delay)
        {
            lock (locker)
            {
                this.itemCount++;

                Thread.Sleep((int)delay);

                Console.WriteLine($"C# 2.0 Items in cart：{itemCount}");
            }
        });

        t.Start(300);

        Thread t1 = new Thread(delegate (object delay)
        {
            lock (locker)
            {
                this.itemCount++;

                Thread.Sleep((int)delay);

                Console.WriteLine($"C# 2.0 Items in cart：{itemCount}");
            }
        });

        t1.Start(100);
    }
}

public class MultiThread30
{
    private int itemCount = 0;
    private object locker = new object();

    public void Run()
    {
        Thread t = new Thread((object delay) =>
        {
            lock (locker)
            {
                this.itemCount++;

                Thread.Sleep((int)delay);

                Console.WriteLine($"C# 3.0 Items in cart：{itemCount}");
            }
        });

        t.Start(300);

        Thread t1 = new Thread((object delay) =>
        {
            lock (locker)
            {
                this.itemCount++;

                Thread.Sleep((int)delay);

                Console.WriteLine($"C# 3.0 Items in cart：{itemCount}");
            }
        });

        t1.Start(100);
    }
}

public class MultiThread40
{
    private int itemCount = 0;
    private object locker = new object();

    public void Run()
    {
        Task t = new Task(() =>
        {
            lock (locker)
            {
                this.itemCount++;

                Thread.Sleep(300);

                Console.WriteLine($"C# 4.0 Items in cart：{itemCount}");
            }
        });

        t.Start();

        Task t1 = new Task(() =>
        {
            lock (locker)
            {
                this.itemCount++;

                Thread.Sleep(100);

                Console.WriteLine($"C# 4.0 Items in cart：{itemCount}");
            }
        });

        t1.Start();
    }
}

public class MultiThreadAync
{
    private int itemCount = 0;
    private object locker = new object();

    public void Run()
    {
        T1();
        T2();
    }

    public async void T1()
    {
        await Task.Delay(3000);

        lock (locker)
        {
            this.itemCount++;

            Console.WriteLine($"C# Aync Items in cart：{itemCount}");
        }
    }

    public async void T2()
    {
        await Task.Delay(1000);

        lock (locker)
        {
            this.itemCount++;

            Console.WriteLine($"C# Aync Items in cart：{itemCount}");
        }
    }
}