实现简单的dos系统，里面有cd命令dir命令type命令还有就是exit命令，通过动态链接库进行加载的。-Simple dos system, the cd command dir command type command there is the exit command to load the dynamic link library.

使用时，先加载，在cad命令栏输入test，就可以动态的逐个往上或往下增减1，不用一个个改。-When in use, the first load, in the CAD command bar input test, you can go up or down the dynamic one by one or 1, do not have to change one by one.