编写程序，要求父进程创建一个子进程，子进程对一个50*50的字符数组赋值，由父进程改变子进程的优先级，观察不同优先级进程使用CPU的时间-Written procedures that require the parent process creates a child process, the child process on a 50* 50 array of characters assigned by the parent process to change the priority of the child process, observe the different priorities of CPU time used by the process