利用C++语言编制一个LL（1）语法分析器，利用LL(1)控制程序根据显示栈栈顶内容、向前看符号以及LL（1）分析表，对输入符号串自上而下的分析过程。可通过消除左递归、提取左因子把非LL(1)文法改造成LL(1)文法。-Compiled using a C++ language LL (1) parser using LL (1) control program according to display the contents of the stack the stack, forward-looking symbols and LL (1) of the table, the input symbol string of top-down analysis . Through the elimination of left recursion, left-factor of the extraction of non-LL (1) grammar transformation into a LL (1) grammar.