词法分析是指将我们编写的文本代码流解析为一个一个的记号，分析得到的记号以供后续语法分析使用。词法分析器的工作是低级别的分析：将字符或者字符序列转化成记号.。-Lexical analysis stream parsing the text code that we write as a token analysis of the resulting mark for subsequent parsing use. Lexical analyzer' s job is low-level a

The main job of the scanner is to identify and return the next token. The value to be returned includes: the token "name" (e.g., INTLITERAL). Token names are defined in the file sym.java the line number in the input file on which the toke