文件夹

一个处理自定义文件夹的类：

class Folders {
public:
	int count(); // returns the number of folders in the list
	Folder item(int index); // returns a folder with the given index
	Folder add(string name); // adds a new folder
	void clear(); // clears the list
};

一个使用自定义文件夹的类：

class Folder {
public:
	int count(); // returns the number of subfolders
	Folder item(int index); // returns a subfolder with the given index
	Folder add(string name); // adds a new subfolder
	string name(); // returns the name of the folder
	void clear(); // clears the list of subfolders
	void destroy(); // destroys the folder an all child subfolders
};