www.pudn.com > LL1.rar > 1.cpp

 
#include 
#include 
using namespace std; 
const int NonterminalNum=5; //非终结符个数 
const int TerminalNum=9; //终结符个数 
char nonterminal[NonterminalNum]={'E', 'A', 'T', 'B','F'}; //定义非终结符 
char terminal[TerminalNum]={'i', '+', '*', '(', ')', 'e','-','/'}; //定义终结符 
 
stack s; 
 
 
    //	1=E->TA;	2=A->+TA;  3=A->e;  	4=A->-TA;	5=T->FB; 
	//  6=B->e; 	7=B->/FB;     8=B->*FB;	9=F->(E);   0=F->id 
void Event0();     
void Event1(); 
void Event2(); 
void Event3(); 
void Event4(); 
void Event5(); 
void Event6(); 
void Event7(); 
void Event8(); 
void Event9(); 
void Error(); 
 
typedef void (*Action)(); 
 
Action ParseTable[NonterminalNum][TerminalNum]={ 
	{Event1, Error, Error, Event1, Error, Error,Error,Error,Error}, 
	{Error, Event2, Error, Error, Event3, Event3,Event3,Event4,Error}, 
	{Event5, Error, Error, Event5, Error, Error, Error, Error,Error}, 
	{Error, Event6, Event8, Error, Event6, Event6,Event6,Event6,Event7,}, 
	{Event0, Error, Error, Event9, Error, Error,Error,Error,Error} 
}; 
 
 
// 定义事件 
 
void Event1() 
{ 
	s.pop(); 
	s.push('A'); 
	s.push('T'); 
}; 
 
void Event2() 
{ 
	s.pop(); 
	s.push('A'); 
	s.push('T'); 
	s.push('+'); 
}; 
 
void Event3() 
{ 
	s.pop(); 
}; 
 
void Event4() 
{ 
	s.pop(); 
	s.push('A'); 
	s.push('T'); 
	s.push('-'); 
}; 
 
void Event5() 
{ 
	s.pop(); 
	s.push('B'); 
	s.push('F'); 
}; 
 
void Event6() 
{ 
	s.pop(); 
}; 
 
void Event7() 
{ 
	s.pop(); 
	s.push('B'); 
	s.push('F'); 
	s.push('/'); 
}; 
void Event8() 
{ 
	s.pop(); 
	s.push('B'); 
	s.push('F'); 
	s.push('*'); 
}; 
void Event9() 
{ 
	s.pop(); 
	s.push(')'); 
	s.push('E'); 
	s.push('('); 
}; 
void Event0() 
{ 
	s.pop(); 
	s.push('i'); 
 
}; 
 
// 出错处理 
 
void Error() 
{ 
	cerr<<"------分析失败!------\n"; 
	exit(1); 
}; 
 
 
// 判断 Token 是终结符还是非终结符 
 
bool isVt(char ch) 
{ 
	for(int i=0; i<9; i++) 
	{ 
		if(terminal[i]==ch) 
			return true; 
		else 
			continue; 
	} 
	return false; 
} 
 
void pushTogether(char nonterminal, char terminal) 
{ 
	switch(nonterminal) 
	{ 
	case 'E': 
		switch(terminal) 
		{ 
		case 'i':	ParseTable[0][0]();	break; 
		case '+':	ParseTable[0][1]();	break; 
		case '*':	ParseTable[0][2]();	break; 
		case '(':	ParseTable[0][3]();	break; 
		case ')':	ParseTable[0][4]();	break; 
		case '$':	ParseTable[0][5]();	break; 
		case 'e':	ParseTable[0][6]();	break; 
        case '-':	ParseTable[0][7]();	break; 
		case '/':	ParseTable[0][8]();	break; 
		case '#':	ParseTable[0][9]();	break; 
		default:	break; 
		} 
		break; 
 
	case 'A': 
		switch(terminal) 
		{ 
		case 'i':	ParseTable[1][0]();	break; 
		case '+':	ParseTable[1][1]();	break; 
		case '*':	ParseTable[1][2]();	break; 
		case '(':	ParseTable[1][3]();	break; 
		case ')':	ParseTable[1][4]();	break; 
		case '$':	ParseTable[1][5]();	break; 
		case 'e':	ParseTable[1][6]();	break; 
        case '-':	ParseTable[1][7]();	break; 
		case '/':	ParseTable[1][8]();	break; 
		case '#':	ParseTable[1][9]();	break; 
		default:	break; 
		} 
		break; 
 
	case 'T': 
		switch(terminal) 
		{ 
		case 'i':	ParseTable[2][0]();	break; 
		case '+':	ParseTable[2][1]();	break; 
		case '*':	ParseTable[2][2]();	break; 
		case '(':	ParseTable[2][3]();	break; 
		case ')':	ParseTable[2][4]();	break; 
		case '$':	ParseTable[2][5]();	break; 
		case 'e':	ParseTable[2][6]();	break; 
        case '-':	ParseTable[2][7]();	break; 
		case '/':	ParseTable[2][8]();	break; 
		case '#':	ParseTable[2][9]();	break; 
		default:	break; 
		} 
		break; 
 
	case 'B': 
		switch(terminal) 
		{ 
		case 'i':	ParseTable[3][0]();	break; 
		case '+':	ParseTable[3][1]();	break; 
		case '*':	ParseTable[3][2]();	break; 
		case '(':	ParseTable[3][3]();	break; 
		case ')':	ParseTable[3][4]();	break; 
		case '$':	ParseTable[3][5]();	break; 
		case 'e':	ParseTable[3][6]();	break; 
        case '-':	ParseTable[3][7]();	break; 
		case '/':	ParseTable[3][8]();	break; 
		case '#':	ParseTable[3][9]();	break; 
		default:	break; 
		} 
		break; 
 
	case 'F': 
		switch(terminal) 
		{ 
		case 'i':	ParseTable[4][0]();	break; 
		case '+':	ParseTable[4][1]();	break; 
		case '*':	ParseTable[4][2]();	break; 
		case '(':	ParseTable[4][3]();	break; 
		case ')':	ParseTable[4][4]();	break; 
		case '$':	ParseTable[4][5]();	break; 
		case 'e':	ParseTable[4][6]();	break; 
        case '-':	ParseTable[4][7]();	break; 
		case '/':	ParseTable[4][8]();	break; 
		case '#':	ParseTable[4][9]();	break; 
		default:	break; 
		} 
		break; 
 
	default: 
		Error(); 
		break; 
	} 
} 
void print(stack  s,char a[],int i) 
{ 
		stack t=s; 
		int	j=0; 
		char b[10]={' '}; 
		while(!t.empty()) 
		{ 
			b[j++]=t.top(); 
			t.pop(); 
		} 
		for(int m=j-1;m>=0;m--) 
			cout<>a[i]; 
	i=0; 
	bool flag=true; 
	while(flag) 
	{ 
	 
		char X=s.top(); 
		if(isVt(X)) 
		{ 
			print(s,a,i); 
			if(X==a[i])	//match 
			{	 
				s.pop(); 
			    i++; 
			} 
			else 
				Error(); 
		} 
		else if(X=='$') 
		{ 
			print(s,a,i); 
			if(X==a[i])	//parse successfully 
			{ 
				flag=false; 
				s.pop(); 
			 
			} 
			else 
				Error(); 
		} 
		else	//reverse, push into s 
		{ 
			print(s,a,i); 
			pushTogether(X, a[i]); 
		} 
	} 
	if(s.empty()) 
cout<<"分析成功!"<TA \nA->+TA\nA->e\nA->-TA\nT->FB\nB->e\nB->/FB\nB->*FB\nF->(E)\nF->i\n"; 
	LL1Parse(); 
}