本例程模拟火车票售票系统。为了满足乘客的需求，必须设很多的售票窗口，每个售票窗口就像一个线程，它们各自运行，共同访问相同的数据——火车票的数量。-The routine simulation of train ticket booking system. In order to meet the needs of passengers, there must be a lot of ticketing window, each ticket window is like a thread, th