算符有限分析法 //程序功能： //根据算符优先分析法，将表达式进行语法分析，判断一个表达式是否正确。 //文法：E→E+E E-E E*E E/E (E) i //　　　　其中i为无符号整数-operator limited analysis / / procedural functions : / / operator under priority analysis, to conduct regular expression syntax analysis, judgment, an expression is correct. / / Grammar : E E E E-E E E * E / E (E) i / / for which i unsigned integers