本程序是采用的LL（1）方法进行的语法分析，而LL（1）的分析方法是属于自上而下的方法。



自上而下分析的基本思想是：对任意输入串，试图用一切可能的方法，从文法开始符号（根结点）出发，自上而下为输入串建立一棵语法树。从推导的角度看，它是从文法的开始符号出发，反复使用各种产生式，寻找与输入串匹配的推导。



在输入之前必须要进行该文法是不是LL（1）文法的判断，然后再构造相应的LL（1）分析表来用预测分析方法进行语法分析，依据下面的文法及分析表来设计程序实现预测分析的分析过程。

-This procedure is used for LL (1) method of syntax analysis, LL (1) methods of analysis are top-down approach.



Top-down analysis of the basic idea is: For any input string, trying to use all possible means, from the grammar start symbol (root node) proceed from top to bottom as the input string to establish a syntax tree. From the derivation of the point of view, it is starting from the grammar start symbol and repeatedly using a variety of productions to find the derivation of the input string matches.



Before you enter must be to carry out the grammar is not LL (1) grammar, the judge, and then construct the corresponding LL (1) Analysis of the table to use predictive analysis method of syntax analysis, based on the following grammar and analysis of the table to the design process to achieve predictable analysis of the analysis.