static void Main(string[] args)

{

    Counter counter = new Counter();

    var t1 = new Thread(() => TestCounter(counter));

    var t2 = new Thread(() => TestCounter(counter));

    t1.Start();

    t2.Start();

    Thread.Sleep(TimeSpan.FromSeconds());//睡眠3秒，保证t1、t2两个线程都运行完毕

    Console.WriteLine(counter.count);

    Console.Read();

}

static void Main(string[] args)

{

    CounterWithLock counterlock = new CounterWithLock();

    var t1 = new Thread(() => TestCounter(counterlock));

    var t2 = new Thread(() => TestCounter(counterlock));

    t1.Start();

    t2.Start();  

    Thread.Sleep(TimeSpan.FromSeconds());//睡眠3秒，保证t1、t2两个线程都运行完毕

    Console.WriteLine(counterlock.count);

    Console.Read();

}

/// <summary>

/// 对同一个变量进行1000次加减操作

/// </summary>

/// <param name="c"></param>

static void TestCounter(CounterBase c)

{

    Console.WriteLine("TestCounter start");

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

    {

        c.Increment();

        c.Decrement();

    }

    Console.WriteLine("TestCounter end");

}

abstract class CounterBase

{

    public abstract void Increment();

    public abstract void Decrement();

}

/// <summary>

/// 没有锁

/// </summary>

class Counter : CounterBase

{

    public int count { get; private set; }

    public override void Increment()

    {

        count ++;

    }

    public override void Decrement()

    {

        count --;

    }

}

/// <summary>

/// 加锁

/// </summary>

class CounterWithLock : CounterBase

{

    private readonly object locker = new object();

    public int count { get; private set; }

    public override void Increment()

    {

        lock (locker)

        {

            count++;

        }

    }

    public override void Decrement()

    {

        lock (locker)

        {

            count--;

        }

    }

}