扫描器又称为词法分析器。起功能是依次扫视字符串形式源程序中的各个字符，逐个识别出其中的单词，并将其转换为内部编码形式的单词符号串作为输出-Scanner is also known as the lexical analyzer. Since function is followed by scanning the source code string in the form of various characters, one by one to identify which words an