yffxq.cpp

超好用的语法语义分析器,希望对诸位有用,简单实用!

#include <iostream>
#include <vector>
#include <string>
#include <sstream>
#include "Stack.h"
#include "LLTable.h"
#include "createT.h"

#define ERROR 0

using namespace std;

int main()
{
	Stack ST;
	Table lltable;
	lltable.Init();
	First_Follow FF;
	FF.createTable(lltable);
	
	string strToken;
	cout<<"请输入要分析的符号串(以#结束):  ";
	cin>>strToken;
	int i = 0;
	char a,X;
	string x = "";
	string M;
	bool flag = true;

	ST.Push('#');
	ST.Push('E');
	a = strToken[0];
	while( flag )
	{
		ST.Seeing();
		ST.Pop(X);//栈顶出栈
		if( (X > 'a' && X < 'z') || X == '+' || X == '*' || X == '(' || X == ')' )
		{  //X属于Vt
			if( X == a ) // X = a
			{
				i++;
				a = strToken[i];
			}
			else
			{
				cout<<"ERROR"<<endl;
				return ERROR;
			}
		}
		else if( X == '#' )
		{
			if( X == a)
				flag = false;
			else
			{
				cout<<"ERROR"<<endl;
				return ERROR;
			}
		}
		else
		{
			x = "";
			if(X == '\'')
			{
				ST.Pop(X);//X='\''时将'前的字符出栈
				x += X;
				x += '\'';
			}
			else 
				x += X;
			M = lltable.find(x,a);//找到X1X2...Xk
			if( M == "ERROR" )
			{
				cout<<"ERROR"<<endl;
				return ERROR;
			}
			else
			{
				if( M[M.length()-1] != '$' )//将Xk,Xk-1,....X1依次压入栈
				{
					char ch;
					int n = M.length()-1;
					ch = M[n];
					while( ch != '>')//一直到'>'前
					{
						if( ch == '\'')
						{
							n--;
							ch = M[n];
							ST.Push( ch );
							ST.Push( '\'');
						}
						else
							ST.Push( ch );
						n--;
						ch = M[n];
					}
				}
				else
					continue;
			}
		}
	}
	cout<<"Success!"<<endl;
	return true;
}