Delete some testing code
Rewrite the file and directory class.
1.Removed the class dir_list because we can just use the system call do the same thing
2.Add the interface class environment,which includes functions about the file and directory stuffs.
3.Correct some code in the console and parser(to face the change of the file and directory interface)
4.Why I did so?Well, just because of the possibility for platform-independent.I take a seek,and I find that most OS's(include WINDOWS and UNIX like)has the same system calls for such things.We could do better with the interface instead of the code closed to OS.