根据哲学家进程间的相互制约关系，设置合理的信号量及信号量初值。 创建5个线程，分别模拟5个哲学家进程。 在哲学家线程之间通过对信号量的P,V操作，实现线程之间的同步关系。(According to the mutual restriction between the philosophers' process, the reasonable signal quantity and the initial value of the signal quantity are set up. Cr