说明：  实现c语言的词法分析器，用文件读取，要求能识别整数、自定义标识符及以下关键字： + - * / < <= == != > >= & && || = ( ) [ ] { } : , void int float char if else while do ! main
(Achieve c language lexical analyzer, using file read, the request can identify integers, custom identifiers and the following keywords:+-*/< < = ==! => > = & & & | | = () [] (): , void int float char if else while do! main)