using System;
using System.Threading;
class Program
{
static int sum = 0;
static void DoWork()
{
lock ((object) 0)
{
for (int i = 0; i < 10000; i++)
{
++sum;
}
}
}
static void Main()
{
for (int i = 0; i < 4; i++)
{
new Thread(DoWork).Start();
}
Thread.Sleep(1000); // ad-hoc wait till threads finish
Console.WriteLine("C# sum: " + sum);
}
}