实现对输入文件的操作:保存文档 , 回到起始行 ,改变当前段的部分内容 , 删除当前, 查找字符串,段跳转, 帮助, 字符数 , 跳至下一行 , 跳至上一行 ,结束任务 ,读文档,改变当前段的全部内容, 阅览文档,写文档, 改为小写 等多种功能-realization of the right to operate the importation documents : to preserve documents, to return to the starting line, change the current part of the contents of the current delete, search string of Jump, help, number of characters, Skip to the next line, jumped on his end tasks, reading documents, change the current of the entire content , read files, write files, read a variety of functions such as lowercase