创建两个子进程,分别计算1~5000和5000~1W的素数 通过信号,用父进程专门完成数的保存.同时开启一个进程读文件, * 并讲数据输出到屏幕(保证不被其它信号干扰) -Create two sub-processes, respectively, calculated 1 ~ 5000 and 5000 ~ 1W the prime number of the parent process through the signal specifically to complete t