自下而上语法分析：LR分析器与错误处理

#include<iostream>
#include<string>
#include<stack>
#include<list>
using namespace std;
class getstring
{
public:list <string> istream;
   stack<string> label;
   bool flag;
   list<string>::iterator getite(int i)
   {
   int j = 0;
   list<string>::iterator it1 = istream.begin();
   while (j != i)
   {
   j++; it1++;
   }
   return it1;
   }
   void getis()
   {
   string s1, s2;
   cout << "请输入表达式：" << endl;
   cin >> s1;
   for (int i = 0; i<s1.size(); i++)
   {
   if (s1[i] == '+' || s1[i] == '*' || s1[i] == '(' || s1[i] == ')')
   {
   s2.push_back(s1[i]); istream.push_back(s2); s2.clear();

   }
   else if (s1[i] == 'i')
   {
   s2.push_back(s1[i]); i++;
   if (s1[i] == 'd') { s2.push_back(s1[i]); istream.push_back(s2); s2.clear(); }
   else { error(); }
   }
   else if (s1[i] == '\0')
   {
   continue;
   }
   else
   {
   error();
   }
   }
   istream.push_back("$"); flag = false;
   }
   void error()
   {
   cout << "错误！" << endl;
   exit(0);
   }
   void test()
   {
   if (label.empty() || istream.empty()) { exit(0); }
   }
   void gototable(string s1, string s2)
   {
   if (s1 == "0"&&s2 == "E")