实现一个文件阅读器，用于显示文本文件，文件的内容以ASCII字符格式和十六进制格式显示。显示屏幕规格为24*80，实现翻页翻行功能等功能-Implement a file reader, used to display text files, the file contents to ASCII character format and hexadecimal format. Display screen size is 24* 80 next page turn to achieve func