说明：  一个用C＃写的词法分析程序 扫描器的工作任务如下： (1) 识别出源程序中的各个基本语法单位 (也称为单词或语法符号)； (2) 删除无用的空白字符、回车字符以及其它与输入介质相关的非实质性字符； (3) 删除注释； (4) 进行词法检查，报告所发现的错误。
(a written using C# lexical analysis procedure of the scanners work tasks are as follows : (1) to identify the source of all the basic grammatical unit (also known as the words or grammatical symbol); (2) delete unwanted blank characters, carriage return characters, and other media related to the importation of non-substantive character; (3) Delete Note; (4) lexical inspection, the report found errors.)