利用vc++ 实现文件的读取，写入，剪贴，复制，撤消，粘贴等功能，来源：Visual C++程序员实用大全（精华版）源代码-use vc achieve document read, write, cut-and-paste, copy, withdraw, pasting, and other functions, sources : Visual C programmers Practical Solutions (best version) source code