,词法分析器,可以识别实数，标志符ID，关键字（if elseif while do while for and or）,Token串.语义分析,遇到合法的字符输出，遇到不合法的字符提示不合法-Lexical analyzer can identify the real number, the identifier ID, keyword (the if elseif while do while for and or), Token string. Semantic analysis, met the legal character output encountered an illegal character prompted illegal