嵌入式系统开发大作业例程，电梯模拟代码，只给出了main函数部分，需要的朋友可以用这个代替软件中的例程keyboard.dsw中的main部分。-Embedded system developing your work routines, elevator simulation code, give only a main function, need friends can part with this instead of in the software of routines. The m