词法分析.cpp

#include <iostream>
#include <cstring>
#include <cstdio>
#include <algorithm>
#include <stack>
#include <fstream>
using namespace std;
const int num_of_keyword=22;
const int num_of_MO=11;
const int num_of_BO=12;
const int num_of_D=9;
const char keyword[50][12]={"break","case","char","continue","do","default","double",
"else","float","for","if","int","include","long","main","return","switch","typedef","void","unsigned","while","iostream"};
const char Monocular_Operator[20]={'+','-','*','/','!','%','~','&','|','^','='};   //单目运算符
const char Binocular_Operator[20][5]={"++","--","&&","||","<=","!=","==",">=","+=","-=","*=","/="}; //双目运算符
const char Delimiter[20]={',','(',')','{','}',';','<','>','#'}; //界符
FILE* file_source=NULL;
ifstream input;
ofstream output;
/******************************************/
//关键字    1
//标识符    2
//常数		3
//运算符	4
//界符		5
/******************************************/
char f(char str[])        //映射到一个字符来表示
{
	if(strcmp(str,keyword[0])==0)
		return 'b';
	if(strcmp(str,keyword[1])==0)
		return 'c';
	if(strcmp(str,keyword[2])==0)   //char  a
		return 'a';
	if(strcmp(str,keyword[3])==0)   //continue   o
		return 'o';
	if(strcmp(str,keyword[4])==0)
		return 'd';
	if(strcmp(str,keyword[5])==0)	//default    n
		return 'n';
	if(strcmp(str,keyword[6])==0)	//double   z
		return 'z';
	if(strcmp(str,keyword[7])==0)
		return 'e';
	if(strcmp(str,keyword[8])==0)	//float  y
		return 'y';
	if(strcmp(str,keyword[9])==0)
		return 'f';
	if(strcmp(str,keyword[10])==0)
		return 'i';
	if(strcmp(str,keyword[11])==0)  //int    h
		return 'h';
	if(strcmp(str,keyword[12])==0)	//include  p
		return 'p';
	if(strcmp(str,keyword[13])==0)
		return 'l';
	if(strcmp(str,keyword[14])==0)
		return 'm';
	if(strcmp(str,keyword[15])==0)
		return 'r';
	if(strcmp(str,keyword[16])==0)
		return 's';
	if(strcmp(str,keyword[17])==0)
		return 't';
	if(strcmp(str,keyword[18])==0)
		return 'v';
	if(strcmp(str,keyword[19])==0)
		return 'u';
	if(strcmp(str,keyword[20])==0)
		return 'w';
	if(strcmp(str,keyword[21])==0)     //iostream   k
		return 'k';
}

char state[100];
int len_state;
//char move[100][100];
char start;
char final[100];
int len_final;
bool is_final[150];

struct NFA_set
{
	char set[100];
	int len=0;
};
char buffer[100];
int buffer_size=0;

NFA_set move[100][100];

char N_state[100];
int N_len_state;
char N_start;
char N_final[100];
int N_len_final;
bool N_is_final[100];

NFA_set new_set[100];
int num_new_set=0;
int dfa[150][150];

bool IsInteger(char a)
{
	if(a>='0' && a<='9')
		return true;
	return false;
}
bool IsLetter(char a)
{
	if(a>='a' && a<='z')
		return true;
	if(a>='A' && a<='Z')
		return true;
	return false;
}
bool IsKeyword(char a[])
{
	int len=strlen(a);
	for(int j=0;j<num_of_keyword;++j)
	{
		if(strlen(keyword[j])==len)
		{
			if(strcmp(keyword[j],a)==0)
				return true;
		}
	}
	return false;
}
bool IsMO(char a)
{
	for(int i=0;i<num_of_MO;++i)
	{
		if(Monocular_Operator[i]==a)
			return true;
	}
	return false;
}
bool IsBO(char a[])
{
	for(int i=0;i<num_of_BO;++i)
	{
		if(strcmp(Binocular_Operator[i],a)==0)
			return true;
	}
	return false;
}
bool IsDelimiter(char a)
{
	for(int i=0;i<num_of_D;++i)
	{
		if(Delimiter[i]==a)
			return true;
	}
	return false;
}
bool Is_In_state(char a)
{
	for(int i=0;i<len_state;++i)
	{
		if(a==state[i])
			return true;
	}
	return false;
}
bool Is_In_final(char a)
{
	for(int i=0;i<len_final;++i)
	{
		if(a==final[i])
			return true;
	}
	return false;
}
bool Is_in_set(char a,NFA_set temp)
{
	for(int i=0;i<temp.len;++i)
	{
		if(a==temp.set[i])
			return true;
	}
	return false;
}

void createNFA()
{

	int N;
	bool flag=true;   //是不是第一个
	char ch;    //用来读 文法左边的
	char nouse;
	char str[10];    //用来读 文法 右边的
	input.open("F:\\编译原理课程设计答辩\\词法分析_文法.txt");
	input>>N;
	while(N--)
	{
		input>>ch>>nouse>>nouse>>str;
		if(flag)
		{
			start=ch;
			flag=false;
		}
		if(!Is_In_state(ch))
		{
			state[len_state++]=ch;
		}
		if(!Is_In_final(str[0]))
		{
			final[len_final++]=str[0];
		}
		if(strlen(str)>1)
		{
			move[ch][str[0]].set[move[ch][str[0]].len++]=str[1];
		}
		else
		{
			//if(str[0]=='@')        //用@表示伊布熊
				//is_final[ch]=true;
			//else
			move[ch][str[0]].set[move[ch][str[0]].len++]='Y';  //终态
		}
	}
}
void showNFA()
{
	for(int i=0;i<100;++i)
	{
		for(int j=0;j<100;++j)
		{
			for(int k=0;k<100;++k)
			{
				if(move[i][j].set[k]!='#')
					cout<<char(i)<<" "<<char(j)<<" "<<k<<" "<<move[i][j].set[k]<<endl;
			}
		}
	}
}
int Is_in(NFA_set temp)   //和已有的newset有没有重复的，有就返回重复的编号
{
	bool flag[100];
	bool flag1;
	for(int i=0;i<temp.len;++i)
	{
		flag[i]=false;
	}
	for(int i=0;i<num_new_set;++i)
	{
		for(int k=0;k<temp.len;++k)
		{
			for(int j=0;j<new_set[i].len;++j)
			{
				if(temp.set[k]==new_set[i].set[j])
				{
					flag[k]=true;
				}
			}
		}
		flag1=true;
		for(int m=0;m<temp.len;++m)
		{
			if(flag[m]==false)
			{
				flag1=false;
				break;
			}
		}
		if(flag1==true)
			return i;
		for(int m=0;m<temp.len;++m)
		{
			flag[m]=false;
		}
	}
	return -1;
}
void get_closure(NFA_set &temp)    //得到一个完整的子集 
{
	for(int i=0;i<temp.len;++i)
	{
		for(int j=0;j<move[temp.set[i]]['@'].len;++j)
		{
			if(!Is_in_set(move[temp.set[i]]['@'].set[j],temp))
			{
				temp.set[temp.len++]=move[temp.set[i]]['@'].set[j];
			}
		}
	}
}
bool Is_contained_Y(NFA_set temp)   //判断是否是终态
{
	for(int i=0;i<temp.len;++i)
	{
		if(temp.set[i]=='Y')
			return true;
	}
	return false;
}
void NFA_to_DFA()
{
	num_new_set=0;
	NFA_set work_set;
	NFA_set worked_set;
	work_set.set[work_set.len++]=start;
	worked_set.len=0;
	stack<NFA_set> s;
	get_closure(work_set);
	s.push(work_set);
	new_set[num_new_set++]=work_set;
	for(int i=0;i<150;++i)
	{
		for(int j=0;j<150;++j)
		{
			dfa[i][j]='-1';
		}
	}
	for(int i=0;i<150;++i)
		is_final[i]=false;
	if(Is_contained_Y(work_set))
		is_final[num_new_set-1]=true;
	while(!s.empty())
	{
		work_set=s.top();
		s.pop();
		for(int i=0;i<len_final;++i)
		{
			for(int j=0;j<work_set.len;++j)
			{
				for(int k=0;k<move[work_set.set[j]][final[i]].len;++k)
				{
					if(move[work_set.set[j]][final[i]].set[k]!='#' && move[work_set.set[j]][final[i]].set[k]!='Y' && !Is_in_set(move[work_set.set[j]][final[i]].set[k],worked_set))
					{
						worked_set.set[worked_set.len++]=move[work_set.set[j]][final[i]].set[k];
					}
					if(move[work_set.set[j]][final[i]].set[k]=='Y' && !Is_in_set(move[work_set.set[j]][final[i]].set[k],worked_set))
					{
						worked_set.set[worked_set.len++]='Y';    //用Y表示终态
					}
				}
			}
			get_closure(worked_set);
			if(worked_set.len>0 && Is_in(worked_set)==-1)
			{
				dfa[num_new_set-1][final[i]]=num_new_set;
				s.push(worked_set);
				new_set[num_new_set++]=worked_set;
				if(Is_contained_Y(worked_set))
				{
					is_final[num_new_set-1]=true;
				}
			}
			if(worked_set.len>0 && Is_in(worked_set)>-1 && final[i]!='@')
			{				
				dfa[Is_in(work_set)][final[i]]=Is_in(worked_set);
			}
			worked_set.len=0;
		}
	}
	/*
	for(int i=0;i<150;++i)
	{
		for(int j=0;j<150;++j)
		{
			if(dfa[i][j]!='-1')
				cout<<i<<" "<<char(j)<<":"<<dfa[i][j]<<endl;
		}
	}
	for(int i=0;i<num_new_set;++i)
	{
		if(is_final[i])
			cout<<i<<" :"<<endl;
	}*/
}
/*
void createDFA()
{
	bool flag=true;   //是不是第一个
	char ch;    //用来读 文法左边的
	char str[10];    //用来读 文法 右边的
	freopen("文法.txt","r",stdin);
	while(scanf("%c->%s",&ch,str)!=EOF)
	{
		if(flag)
		{
			start=ch;
			flag=false;
		}
		if(!Is_In_state(ch))
		{ 
			state[len_state++]=ch;
		}
		if(strlen(str)>1)
		{
			if(!Is_In_final(str[0]))
			{
				final[len_final++]=str[0];
			}
			move[ch][str[0]]=str[1];
		}
		else
		{
			if(str[0]=='@')        //用@表示伊布熊
				is_final[ch]=true;
			else
				move[ch][str[0]]='0';  //终态
		}
	}
}
bool DFA(char str[])
{
	char now_state=start;
	for(int i=0;i<strlen(str);++i )
	{
		now_state=move[now_state][str[i]];
		if(now_state==NULL)
			return false;
	}
	if(now_state=='0')
		return true;
	return false;
}*/
bool DFA(char str[])
{
	char now_state=0;
	for(int i=0;i<strlen(str);++i )
	{
		now_state=dfa[now_state][str[i]];
		if(now_state==-1)
			return false;
	}
	if(is_final[now_state]==true)
		return true;
	return false;
}
void scan()
{
	char str[100];
	char ch;
	int i,j;
	int point;
	int flag;

	ch=fgetc(file_source);
	bool finish=false;
	while(!finish)
	{
	 	flag=-1;
		point=0;
		if(IsInteger(ch))     //多一个ch
		{
			flag=1;
			str[point++]=ch;
			ch=fgetc(file_source);
			while(IsLetter(ch) || IsInteger(ch) || ch=='.' || ch=='+' || ch=='-')
			{
				flag=1;
				str[point++]=ch;
				ch=fgetc(file_source);
			}
			str[point]='\0';
		}
		if(flag==1)
		{
			if(DFA(str))
			{
				cout<<str<<" "<<"常量"<<endl;
				output<<3;
			}
			else
			{
				cout<<str<<" "<<"出错，不是常量"<<endl;
			}
			point=0;
			flag=-1;
		}
		if(IsLetter(ch))
		{
			flag=2;
			str[point++]=ch;
			ch=fgetc(file_source);
			while(IsLetter(ch) || IsInteger(ch))
			{
				flag=2;
				str[point++]=ch;
				ch=fgetc(file_source);
			}
			str[point]='\0';
		}
		if(flag==2)
		{
			if(IsKeyword(str))
			{
				cout<<str<<" "<<"关键字"<<endl;
				output<<f(str);
			}
			else
			{
				if(DFA(str))
				{
					cout<<str<<" "<<"标识符"<<endl;
					output<<2;
				}
				else
				{
					cout<<str<<" "<<"出错，不是标识符"<<endl;
				}
			}
			point=0;
			flag=-1;
		}
		/*while(IsInteger(ch) || ch=='.')
		{
			flag=2;
			str[point++]=ch;
			if((ch=fgetc(file_source))==EOF)
			{
				finish=true;
				break;
			}
		}
		str[point]='/0';
		if(flag==2)
		{
			if(DFA(str))
			{
				cout<<str<<" "<<"数字"<<endl;
				output<<3;
			}
			else
			{
				cout<<str<<" "<<"出错不是数字"<<endl;
			}
			flag=-1;
		}*/
		if(IsDelimiter(ch))
		{
			cout<<ch<<" "<<"界符"<<endl;
			if(ch=='#')
				output<<'*';
			else
				output<<ch;
			if((ch=fgetc(file_source))==EOF)
			{
				finish=true;
				break;
			}
		}
		if(IsMO(ch))
		{
			str[point++]=ch;
			if((ch=fgetc(file_source))==EOF)
			{
				finish=true;
			}
			str[point++]=ch;
			str[point]='\0';
			if(finish==false && IsBO(str))
			{
				cout<<str<<" "<<"双目运算符"<<endl;
				//output<<4;
				ch=fgetc(file_source);
			}
			else
			{
				cout<<str[0]<<" "<<"单目运算符"<<endl;
				output<<str[0];
			}
			point=0;
		}

		if(ch==' ' || ch=='\n' || ch=='\t')
		{
			if((ch=fgetc(file_source))==EOF)
			{
				finish=true;
				break;
			}
			continue;
		}
	}
	output<<'#';
}
void init()
{ 
	len_final=0;
	len_state=0;
	for(int i=0;i<100;++i)
	{
		//is_final[i]=false;
		for(int j=0;j<100;++j)
			for(int k=0;k<100;++k)
				move[i][j].set[k]='#';
	}
}
void show()
{
	for(int i=0;i<num_new_set;++i)
	{
		cout<<i<<"的set"<<endl;
		for(int j=0;j<new_set[i].len;++j)
		{
			
			cout<<new_set[i].set[j]<<" ";
		}
		cout<<endl;
	}
}
int main()
{
	init();
	len_final=0;
	len_state=0;
	createNFA();
	NFA_to_DFA();
	//show();
	file_source=fopen("词法分析_源程序.txt","r+");
	output.open("F:\\编译原理课程设计答辩\\output.txt");
	scan();
	fclose(file_source);
	output.close();
	return 0;
}