说明：  创建一个控制台进程，此进程包含n个线程。用这n个线程来表示n个读者或写者。每个线程按相应测试数据文件的要求进行读写操作。用信号量机制实现读者优先的读者——写入者问题。
(the process of creating a console, this process contain n threads. Use of these n threads to express n readers who write. Each thread according to the corresponding test data document requests and write. Using signal volume mechanisms readers priority readers-- into the problem.)