普通文件和目录编程

1.　　编写程序mycp.c，实现从命令行读入文件的复制功能，用原始文件系统调用。

2.　　编写程序mycat.c，实现文件内容的显示，用原始文件系统调用实现。

3.　　用流文件系统函数重新编写上面的程序。

. 调用目录函数，编写程序myls.c，实现按下面格式显示当前目录文件列表：文件名　　文件大小 文件创建时间

注意研究文件创建时间的转换，即如何把从1970年1月1日起的秒数转换为表示时间的字符串，从而显示出来，注意研究asctime（）函数和ctime（）函数的用法。

-Ordinary files and directories programming. Program mycp.c copy function that reads files from the command line with the original file system calls. 2. Write programs mycat.c, and display the contents of the file, the original file system call implementation. 3, with the stream file system function to re-write the above program. Call directory function, write program myls.c, and display the current directory file list in the following format: file name, file size of the file creation time attention to studying the conversion of the file creation time, that is how the number of seconds since January 1, 1970 converted to a string that represents the time to show up, pay attention to the research asctime () function ctime () function usage.