class Program

    {

        

static 

void Main(

string[] args)

        {

            Console.WriteLine(

"

Increment counter

");

            

var c = 

new Counter();

            

var t1 = 

new Thread(() => TestCounter(c));

            

var t2 = 

new Thread(() => TestCounter(c));

            

var t3 = 

new Thread(() => TestCounter(c));

            t1.Start();

            t2.Start();

            t3.Start();

            t1.Join();

            t2.Join();

            t3.Join();

            Console.WriteLine(

"

Total Count:{0}

", c.Count);

            Console.WriteLine(

"

end Increment

");

            

var c1 = 

new CounterNoLock();

            t1 = 

new Thread(() => TestCounter(c));

            t2 = 

new Thread(() => TestCounter(c));

            t3 = 

new Thread(() => TestCounter(c));

            t1.Start();

            t2.Start();

            t3.Start();

            t1.Join();

            t2.Join();

            t3.Join();

            Console.WriteLine(

"

Total Count:{0}

", c1.Count);

            Console.WriteLine(

"

end CounterNoLock

");

        }

        

static 

void TestCounter(CounterBase c)

        {

            

for (

int i = 

0; i < 

10000; i++)

            {

                c.Increment();

                c.Decrement();

            }

        }

        

class Counter : CounterBase

        {

            

private 

int _count;

            

public 

int Count { 

get { 

return _count; } }

            

public 

override 

void Increment()

            {

                _count++;

            }

            

public 

override 

void Decrement()

            {

                _count--;

            }

        }

        

class CounterNoLock : CounterBase

        {

            

private 

int _count;

            

public 

int Count { 

get { 

return _count; } }

            

public 

override 

void Increment()

            {

                Interlocked.Increment(

ref _count);

            }

            

public 

override 

void Decrement()

            {

                Interlocked.Decrement(

ref _count);

            }

        }

        

abstract 

class CounterBase

        {

            

public 

abstract 

void Increment();

            

public 

abstract 

void Decrement();

        }

    }