程序1处理unicode字符串，程序2 进行资源读取和字符串类的CString 扩展类 程序3 不依赖系统的CString类，程序4CUnicodeString类，程序５实现基本功能的 字符串类-procedures for handling a unicode string, two procedures resources, and the string read like CString extension of the class three procedures do not re