生成一个随机产生的字符型数据组成文件将该文件所有字节进行倒放，存入原文件，即将文件中首字节与尾字节兑换，次字节与次字节对换，以此类推。编写了两个程序，一个程序采用常规的文件访问方法，另一个程序采用内存映射文件方法，两者进行比较。-Composed of character data file to generate a randomly generated bytes rewind all the files, stored in the original file, will file the first byte and trail byte exchange, and sub-sub-byte-for-byte, and so on . Write two programs, one program file access using conventional methods, another program uses memory mapped files method to compare the two.