语法分析 按照崔老师上午授课内容写出来框架"/>
编译原理 第二次实验 语法分析 按照崔老师上午授课内容写出来框架
老师授课内容：
注意：
调用advance(),依次读取一个词法分析得到的结果，得到的结果形式为 （种别码，D） 其中D 可以为 + - * / 数字 。
定义：
sym 得到的是每次取得结果 （ 和 ，前面中间的值，即种别码。 种别码时string类型。
举例：
以下程序用来判断是+ 或者 -
以下程序用来判断 * 或者 /
以下程序用来判断 （
以下程序用来判断 ）
以下程序用来判断数字（注意数字不用管数值是多少）
以下程序用来报错：
printf("Error!\n");exit(1);
程序框架1如下：
如果运行不了，可以试试框架2
#include<bits/stdc++.h>
#include <iostream>
#include <map>
#include <algorithm>
#include <string>
#include<string.h>
#include<stdio.h>
#include<time.h>
#include<sstream>using namespace std;template <class Type> Type stringToNum(const string& str)
{istringstream iss(str);Type num;iss >> num;return num;
}int num=0;
int sum=0;ifstream infile("d.txt");//词法分析的结果或语法分析的输入
string str;//string变量进行字符识别
string sym; //指针
string sym1;
int temp=0;//int expressionAnalysis();//表达式分析
//int termAnaysis();//项分析
//int factorAnalysis();//因子分析
//int advance();
int E();
int E_plus();
int T();
int T_plus();
int F();int conterr=0;//记录错误
int lpnum=0;//记录左括号
int found;//提取字符串中指针的位置
string sym2;
int found1;
int flag=0;//记录往后移动一个指针SYM是否正确
string s;//用来保存要分析的字符串
struct _2tup
{string token;int id;
};int advance() //SYM的移动
{if(!getline(infile,str)) //从文件中提取字符{return 0;}
// cout<<str<<endl;s+=str;
// cout<<s<<endl;found=str.find(',',0);found1=str.find(')',0);
// cout<<found1<<endl;if(found==-1) //当为error的时候，没有‘，’{conterr++;return 0;
// cout<<"语法错误 识别字符错误"<<endl;
// return -1;}if(temp==1)sym1=sym;sym=str.substr(1,found-1);sym2=str.substr(found+1,found1-found-1);num=stringToNum<int>(sym2);
// cout<<num<<endl;return 1;
}int F()
{}
int T_plus()
{}
int T()
{}int E_plus()
{}int E()
{T();E_plus();}
void yufafenxi()//语法分析
{
// freopen("CON", "w", stdout);//结果在控制台上输出
// flag=advance();
// if(flag)-
// {advance();E();
// advance();if(strcmp(str.data(),"#")!=0){printf("%s\n",s.data());printf("Error\n");}else{cout<<"OK: "<<s<<endl;}
// }
// if(flag!=-1 && !conterr)
// {
// cout<<"正确："<<s<<endl;
// }}string instr;//输入符号串
int index;//当前输入符号读入字符的位置
char character;//全局变量字符，存放最新读入的字符
string token;//字符数组，存放已读入的字符序列
map<string, int> Symbol;//标识符集
map<string, int> Digit;//常数集
map<string, int> other;//other
map<string, int>::iterator ite;
const int len = 100;
string Reserve[len];//保留字表
map<string,int> type;
//void init_Reserve() //构造保留字表的函数
//{
// Reserve[1] = "begin";
// Reserve[2] = "end";
// Reserve[3] = "if";
// Reserve[4] = "then";
// Reserve[5] = "while";
// Reserve[6] = "do";
// Reserve[7] = "const";
// Reserve[8] = "var";
// Reserve[9] = "call";
// Reserve[10] = "procedure";
//
//}
void getChar() //读入一个字符
{character = instr[index++];
}
void getnbc() //读入非空白字符
{while (character == ' '){getChar();}
}
void concat() //连接字符串
{token = token + character;
}
bool letter() //判断是否为字母
{if ((character >= 'A'&&character <= 'Z') || (character >= 'a'&&character <= 'z'))return true;return false;
}
bool digit() //判断是否为数字
{if (character >= '0'&&character <= '9')return true;return false;
}
void retract() //回退字符的函数
{
// character = ' ';index--;
}
int reserve() //匹配保留字符
{for (int i = 0; i < len; i++)if (Reserve[i] == token)return i;return -1;
}
void symbol()
{ite = Symbol.find(token);if (ite != Symbol.end()){
// return ite->first;return ;}else{Symbol[token] = Symbol.size();return ;
// return token;}
}
void constant()
{ite = Digit.find(token);if (ite != Digit.end()){
// return ite->first;return ;}else{Digit[token] = Digit.size();return ;
// return token;}
}
void Three()
{ite = other.find(token);if (ite != other.end()){return ;
// return ite->first;}else{other[token] = other.size();return ;
// return token;}
}
void error()
{cout << token << "\t-->\t该单词不存在" << endl;
}
//词法分析函数，逐个识别单词
string LexAnalyze()
{token = "";getChar();getnbc();string val;
// int num = -1;if(character>='a'&&character<='z' || character>='A'&&character<='Z'){while (letter() || digit()) //为字母或数字{concat();//追加到token末尾// if(token=="odd")
// {
// getChar();
// Three();
// return ;
// }getChar();//读取下一个字符}if(token=="odd"){getChar();Three();return 0;}retract();//回退一个字符{
// val = symbol();//查看标识符表symbol();}}else if(character>='0' && character<='9'){int flag=0;while (character>='0' && character<='9' || character>='a' && character<='z' || character>='A' && character <='Z'){if(character>='0' && character<='9')concat();if(character>='a' && character<='z' || character>='A' && character <='Z'){concat();flag=1;}getChar();}if(flag==1){error();return 0;}retract();
// val = constant();//查看常数表constant();}else if(character=='<'){concat();getChar();if (character == '='){concat();Three();
//返回<=符号}else if(character=='>'){concat();Three();}else{retract();Three();
//返回<符号}}else if(character=='>'){concat();getChar();if (character == '='){concat();Three();
//返回>=符号}else{retract();Three();
//返回>符号}}else if(character=='='){concat();getChar();if (character == '='){concat();Three();
//返回==符号}else{retract();Three();
//返回=符号}}else if(character==':'){concat();getChar();if (character == '='){concat();Three();}else{cout<<token<<endl;error();return 0;}}else if(character=='+'){concat();Three();}else if(character=='-'){concat();Three();}else if(character=='*'){concat();Three();}else if(character=='/'){concat();Three();}else if(character=='('){concat();Three();}else if(character==')'){concat();Three();}else if(character==','){concat();Three();}else if(character=='.'){concat();Three();}else if(character==';'){concat();Three();}else if(character=='#'){concat();return token;}else{error();return 0;}return token;}
void show_table()
{cout << "\n==================" << "标识符" << "==================" << endl;
// cout << "标识符\t\t类别编码\t表中位置" << endl;for (ite=Symbol.begin(); ite != Symbol.end(); ite++){
// int flag=0;
// for (int i = 0; i < len; i++)
// {cout<<Reserve[i]<<endl;
// if (Reserve[i] == ite->first)
// {
// cout<<ite->first<<"是保留字"<<" ";
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;
// flag=1;
// break;
// }
//
//
// }
// if(flag==0)
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);if(iter!=type.end())cout << "("<<iter->second <<","<<ite->second<<")" << endl;elsecout << "("<<type.size() <<","<<ite->second<<")" << endl;}cout << "\n==================" << "常数表" << "==================" << endl;
// cout << "常量值\t\t类别编码\t表中位置" << endl;for (ite = Digit.begin(); ite != Digit.end(); ite++){
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);
// if(iter!=type.end())
// cout << "("<<iter->second <<","<<ite->second<<")" << endl;
// elsecout << "("<<type.size()-1 <<","<<ite->second<<")" << endl;}cout << "\n==================" << "算符、界符" << "==================" << endl;for (ite = other.begin(); ite != other.end(); ite++){
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);cout << "("<<iter->second <<","<<ite->second<<")" << endl;
// cout<<iter->second<<endl;}
}
int main()
{
// clock_t start,finish;
// double totaltime;
// start=clock();type["begin"]=type.size();type["end"]=type.size();type["if"]=type.size();type["then"]=type.size();type["while"]=type.size();type["do"]=type.size();type["const"]=type.size();type["var"]=type.size();type["call"]=type.size();type["procedure"]=type.size();type["+"]=type.size();type["-"]=type.size();type["*"]=type.size();type["/"]=type.size();type["odd"]=type.size();type["="]=type.size();type["<>"]=type.size();type["<"]=type.size();type[">"]=type.size();type["<="]=type.size();type[">="]=type.size();type[":="]=type.size();type["("]=type.size();type[")"]=type.size();type[","]=type.size();type["."]=type.size();type[";"]=type.size();type["常数"]=type.size();type["标识符"]=type.size();// init_Reserve();//保留字表初始化Symbol.clear();//标识符集初始化Digit.clear();//常数集初始化index = 0;character = ' ';token = "";cout << "请输入待词法分析的源程序代码：输入文件结束符结束输入\n" << endl;//源程序代码输入处理
// instr="var a,b,c; a:=1; b:=2; c:=a+b";char ch[1000];string ins;
// printf("%d\n",gets(ch));
// printf("\n%d",&ch[1]);
// cout<<gets(ch)<<endl;while(gets(ch)){FILE *fp;
// char str[1000];map<string,int>::iterator iter;if((fp=fopen("d.txt","w"))==NULL){printf("error occur!\n");exit(1);}if((fp=fopen("d.txt","a"))==NULL){printf("error occur!\n");exit(1);}// ins=ch;instr=ch;index=0;while (index < instr.size()){char* str=(char*)LexAnalyze().data();
// fprintf(fp,"%s\n",str);
// cout<<str<<endl;if(strcmp(str,"#")==0){
// printf("*");fprintf(fp,"%s",str);}else{iter=type.find(str);if(iter!=type.end())// if(index==instr.size())fprintf(fp,"(%d,%s)\n",iter->second,str);
// else
// fprintf(fp,"(%d,%s)\n",iter->second,str);else{iter=Digit.find(str);if(iter!=Digit.end())// if(index==instr.size())fprintf(fp,"(28,%s)\n",str);
// else
// fprintf(fp,"(28,%s)\n",str);}}}fclose(fp);// cout<<instr<<endl;memset(ch,0,sizeof(ch));}yufafenxi();// cout<<instr<<endl;
// string in;
// while (cin >> in&&in != "@")
// {
// instr = instr + " " + in;
// }//识别二元组初始化
// while (index < instr.size())
// {
// LexAnalyze();
// }//展示构造的各种词汇表show_table();// finish=clock();
// totaltime=(double)(finish-start)/CLOCKS_PER_SEC;
// cout<<totaltime<<endl;
// //system("pause");return 0;}
框架2
//#include<bits/stdc++.h>
#include <fstream>
#include <iostream>
#include <map>
#include <algorithm>
#include <string>
#include<string.h>
#include<stdio.h>
#include<time.h>
#include<sstream>using namespace std;template <class Type> Type stringToNum(const string& str)
{istringstream iss(str);Type num;iss >> num;return num;
}int num=0;
int sum=0;ifstream infile("d.txt");//词法分析的结果或语法分析的输入
string str;//string变量进行字符识别
string sym; //指针
string sym1;
int temp=0;//int expressionAnalysis();//表达式分析
//int termAnaysis();//项分析
//int factorAnalysis();//因子分析
//int advance();
int E();
int E_plus();
int T();
int T_plus();
int F();int conterr=0;//记录错误
int lpnum=0;//记录左括号
int found;//提取字符串中指针的位置
string sym2;
int found1;
int flag=0;//记录往后移动一个指针SYM是否正确
string s;//用来保存要分析的字符串
struct _2tup
{string token;int id;
};int advance() //SYM的移动
{if(!getline(infile,str)) //从文件中提取字符{return 0;}
// cout<<str<<endl;s+=str;
// cout<<s<<endl;found=str.find(',',0);found1=str.find(')',0);
// cout<<found1<<endl;if(found==-1) //当为error的时候，没有‘，’{conterr++;return 0;
// cout<<"语法错误 识别字符错误"<<endl;
// return -1;}if(temp==1)sym1=sym;sym=str.substr(1,found-1);sym2=str.substr(found+1,found1-found-1);num=stringToNum<int>(sym2);
// cout<<num<<endl;return 1;
}int F()
{}
int T_plus()
{}
int T()
{}int E_plus()
{}int E()
{T();E_plus();}
void yufafenxi()//语法分析
{
// freopen("CON", "w", stdout);//结果在控制台上输出
// flag=advance();
// if(flag)-
// {advance();E();
// advance();if(strcmp(str.data(),"#")!=0){printf("%s\n",s.data());printf("Error\n");}else{cout<<"OK: "<<s<<endl;}
// }
// if(flag!=-1 && !conterr)
// {
// cout<<"正确："<<s<<endl;
// }}string instr;//输入符号串
int index;//当前输入符号读入字符的位置
char character;//全局变量字符，存放最新读入的字符
string token;//字符数组，存放已读入的字符序列
map<string, int> Symbol;//标识符集
map<string, int> Digit;//常数集
map<string, int> other;//other
map<string, int>::iterator ite;
const int len = 100;
string Reserve[len];//保留字表
map<string,int> type;
//void init_Reserve() //构造保留字表的函数
//{
// Reserve[1] = "begin";
// Reserve[2] = "end";
// Reserve[3] = "if";
// Reserve[4] = "then";
// Reserve[5] = "while";
// Reserve[6] = "do";
// Reserve[7] = "const";
// Reserve[8] = "var";
// Reserve[9] = "call";
// Reserve[10] = "procedure";
//
//}
void getChar() //读入一个字符
{character = instr[index++];
}
void getnbc() //读入非空白字符
{while (character == ' '){getChar();}
}
void concat() //连接字符串
{token = token + character;
}
bool letter() //判断是否为字母
{if ((character >= 'A'&&character <= 'Z') || (character >= 'a'&&character <= 'z'))return true;return false;
}
bool digit() //判断是否为数字
{if (character >= '0'&&character <= '9')return true;return false;
}
void retract() //回退字符的函数
{
// character = ' ';index--;
}
int reserve() //匹配保留字符
{for (int i = 0; i < len; i++)if (Reserve[i] == token)return i;return -1;
}
void symbol()
{ite = Symbol.find(token);if (ite != Symbol.end()){
// return ite->first;return ;}else{Symbol[token] = Symbol.size();return ;
// return token;}
}
void constant()
{ite = Digit.find(token);if (ite != Digit.end()){
// return ite->first;return ;}else{Digit[token] = Digit.size();return ;
// return token;}
}
void Three()
{ite = other.find(token);if (ite != other.end()){return ;
// return ite->first;}else{other[token] = other.size();return ;
// return token;}
}
void error()
{cout << token << "\t-->\t该单词不存在" << endl;
}
//词法分析函数，逐个识别单词
string LexAnalyze()
{token = "";getChar();getnbc();string val;
// int num = -1;if(character>='a'&&character<='z' || character>='A'&&character<='Z'){while (letter() || digit()) //为字母或数字{concat();//追加到token末尾// if(token=="odd")
// {
// getChar();
// Three();
// return ;
// }getChar();//读取下一个字符}if(token=="odd"){getChar();Three();return 0;}retract();//回退一个字符{
// val = symbol();//查看标识符表symbol();}}else if(character>='0' && character<='9'){int flag=0;while (character>='0' && character<='9' || character>='a' && character<='z' || character>='A' && character <='Z'){if(character>='0' && character<='9')concat();if(character>='a' && character<='z' || character>='A' && character <='Z'){concat();flag=1;}getChar();}if(flag==1){error();return 0;}retract();
// val = constant();//查看常数表constant();}else if(character=='<'){concat();getChar();if (character == '='){concat();Three();
//返回<=符号}else if(character=='>'){concat();Three();}else{retract();Three();
//返回<符号}}else if(character=='>'){concat();getChar();if (character == '='){concat();Three();
//返回>=符号}else{retract();Three();
//返回>符号}}else if(character=='='){concat();getChar();if (character == '='){concat();Three();
//返回==符号}else{retract();Three();
//返回=符号}}else if(character==':'){concat();getChar();if (character == '='){concat();Three();}else{cout<<token<<endl;error();return 0;}}else if(character=='+'){concat();Three();}else if(character=='-'){concat();Three();}else if(character=='*'){concat();Three();}else if(character=='/'){concat();Three();}else if(character=='('){concat();Three();}else if(character==')'){concat();Three();}else if(character==','){concat();Three();}else if(character=='.'){concat();Three();}else if(character==';'){concat();Three();}else if(character=='#'){concat();return token;}else{error();return 0;}return token;}
void show_table()
{cout << "\n==================" << "标识符" << "==================" << endl;
// cout << "标识符\t\t类别编码\t表中位置" << endl;for (ite=Symbol.begin(); ite != Symbol.end(); ite++){
// int flag=0;
// for (int i = 0; i < len; i++)
// {
// cout<<Reserve[i]<<endl;
// if (Reserve[i] == ite->first)
// {
// cout<<ite->first<<"是保留字"<<" ";
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;
// flag=1;
// break;
// }
//
//
// }
// if(flag==0)
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);if(iter!=type.end())cout << "("<<iter->second <<","<<ite->second<<")" << endl;elsecout << "("<<type.size() <<","<<ite->second<<")" << endl;}cout << "\n==================" << "常数表" << "==================" << endl;
// cout << "常量值\t\t类别编码\t表中位置" << endl;for (ite = Digit.begin(); ite != Digit.end(); ite++){
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);
// if(iter!=type.end())
// cout << "("<<iter->second <<","<<ite->second<<")" << endl;
// elsecout << "("<<type.size()-1 <<","<<ite->second<<")" << endl;}cout << "\n==================" << "算符、界符" << "==================" << endl;for (ite = other.begin(); ite != other.end(); ite++){
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);cout << "("<<iter->second <<","<<ite->second<<")" << endl;
// cout<<iter->second<<endl;}
}
int main()
{
// clock_t start,finish;
// double totaltime;
// start=clock();type["begin"]=type.size();type["end"]=type.size();type["if"]=type.size();type["then"]=type.size();type["while"]=type.size();type["do"]=type.size();type["const"]=type.size();type["var"]=type.size();type["call"]=type.size();type["procedure"]=type.size();type["+"]=type.size();type["-"]=type.size();type["*"]=type.size();type["/"]=type.size();type["odd"]=type.size();type["="]=type.size();type["<>"]=type.size();type["<"]=type.size();type[">"]=type.size();type["<="]=type.size();type[">="]=type.size();type[":="]=type.size();type["("]=type.size();type[")"]=type.size();type[","]=type.size();type["."]=type.size();type[";"]=type.size();type["常数"]=type.size();type["标识符"]=type.size();// init_Reserve();//保留字表初始化Symbol.clear();//标识符集初始化Digit.clear();//常数集初始化index = 0;character = ' ';token = "";cout << "请输入待词法分析的源程序代码：输入文件结束符结束输入\n" << endl;//源程序代码输入处理
// instr="var a,b,c; a:=1; b:=2; c:=a+b";char ch[1000];string ins;
// printf("%d\n",gets(ch));
// printf("\n%d",&ch[1]);
// cout<<gets(ch)<<endl;while(gets(ch)){FILE *fp;
// char str[1000];map<string,int>::iterator iter;if((fp=fopen("d.txt","w"))==NULL){printf("error occur!\n");exit(1);}if((fp=fopen("d.txt","a"))==NULL){printf("error occur!\n");exit(1);}// ins=ch;instr=ch;index=0;while (index < instr.size()){char* str=(char*)LexAnalyze().data();
// fprintf(fp,"%s\n",str);
// cout<<str<<endl;if(strcmp(str,"#")==0){
// printf("*");fprintf(fp,"%s",str);}else{iter=type.find(str);if(iter!=type.end())// if(index==instr.size())fprintf(fp,"(%d,%s)\n",iter->second,str);
// else
// fprintf(fp,"(%d,%s)\n",iter->second,str);else{iter=Digit.find(str);if(iter!=Digit.end())// if(index==instr.size())fprintf(fp,"(28,%s)\n",str);
// else
// fprintf(fp,"(28,%s)\n",str);}}}fclose(fp);// cout<<instr<<endl;memset(ch,0,sizeof(ch));}yufafenxi();// cout<<instr<<endl;
// string in;
// while (cin >> in&&in != "@")
// {
// instr = instr + " " + in;
// }//识别二元组初始化
// while (index < instr.size())
// {
// LexAnalyze();
// }//展示构造的各种词汇表show_table();// finish=clock();
// totaltime=(double)(finish-start)/CLOCKS_PER_SEC;
// cout<<totaltime<<endl;
// //system("pause");return 0;}
词法分析得到的结果存放在同级目录 d.txt 中。
程序：
//#include<bits/stdc++.h>
#include <fstream>
#include <iostream>
#include <map>
#include <algorithm>
#include <string>
#include<string.h>
#include<stdio.h>
#include<time.h>
#include<sstream>using namespace std;template <class Type> Type stringToNum(const string& str)
{istringstream iss(str);Type num;iss >> num;return num;
}int num=0;
int sum=0;ifstream infile("d.txt");//词法分析的结果或语法分析的输入
string str;//string变量进行字符识别
string sym; //指针
string sym1;
int temp=0;//int expressionAnalysis();//表达式分析
//int termAnaysis();//项分析
//int factorAnalysis();//因子分析
//int advance();
int E();
int E_plus();
int T();
int T_plus();
int F();int conterr=0;//记录错误
int lpnum=0;//记录左括号
int found;//提取字符串中指针的位置
string sym2;
int found1;
int flag=0;//记录往后移动一个指针SYM是否正确
string s;//用来保存要分析的字符串
struct _2tup
{string token;int id;
};int advance() //SYM的移动
{if(!getline(infile,str)) //从文件中提取字符{return 0;}
// cout<<str<<endl;s+=str;
// cout<<s<<endl;found=str.find(',',0);found1=str.find(')',0);
// cout<<found1<<endl;if(found==-1) //当为error的时候，没有‘，’{conterr++;return 0;
// cout<<"语法错误 识别字符错误"<<endl;
// return -1;}if(temp==1)sym1=sym;sym=str.substr(1,found-1);sym2=str.substr(found+1,found1-found-1);num=stringToNum<int>(sym2);
// cout<<num<<endl;return 1;
}int F()
{if(sym=="28"){advance();}else{if(sym=="23"){advance();E();if(sym=="24"){advance();}else{printf("Error!\n");exit(1);}}else{printf("Error!\n");exit(1);}}return 0;}
int T_plus()
{if(sym=="13" || sym=="14") // 如果是 * /{advance();T();E_plus();}
}
int T()
{F();T_plus();}int E_plus()
{if(sym=="11" || sym=="12") // 如果是+ 或者 -{advance();T();E_plus();}
}int E()
{T();E_plus();}
void yufafenxi()//语法分析
{
// freopen("CON", "w", stdout);//结果在控制台上输出
// flag=advance();
// if(flag)-
// {advance();E();
// advance();if(strcmp(str.data(),"#")!=0){printf("%s\n",s.data());printf("Error\n");}else{cout<<"OK: "<<s<<endl;}
// }
// if(flag!=-1 && !conterr)
// {
// cout<<"正确："<<s<<endl;
// }}string instr;//输入符号串
int index;//当前输入符号读入字符的位置
char character;//全局变量字符，存放最新读入的字符
string token;//字符数组，存放已读入的字符序列
map<string, int> Symbol;//标识符集
map<string, int> Digit;//常数集
map<string, int> other;//other
map<string, int>::iterator ite;
const int len = 100;
string Reserve[len];//保留字表
map<string,int> type;
//void init_Reserve() //构造保留字表的函数
//{
// Reserve[1] = "begin";
// Reserve[2] = "end";
// Reserve[3] = "if";
// Reserve[4] = "then";
// Reserve[5] = "while";
// Reserve[6] = "do";
// Reserve[7] = "const";
// Reserve[8] = "var";
// Reserve[9] = "call";
// Reserve[10] = "procedure";
//
//}
void getChar() //读入一个字符
{character = instr[index++];
}
void getnbc() //读入非空白字符
{while (character == ' '){getChar();}
}
void concat() //连接字符串
{token = token + character;
}
bool letter() //判断是否为字母
{if ((character >= 'A'&&character <= 'Z') || (character >= 'a'&&character <= 'z'))return true;return false;
}
bool digit() //判断是否为数字
{if (character >= '0'&&character <= '9')return true;return false;
}
void retract() //回退字符的函数
{
// character = ' ';index--;
}
int reserve() //匹配保留字符
{for (int i = 0; i < len; i++)if (Reserve[i] == token)return i;return -1;
}
void symbol()
{ite = Symbol.find(token);if (ite != Symbol.end()){
// return ite->first;return ;}else{Symbol[token] = Symbol.size();return ;
// return token;}
}
void constant()
{ite = Digit.find(token);if (ite != Digit.end()){
// return ite->first;return ;}else{Digit[token] = Digit.size();return ;
// return token;}
}
void Three()
{ite = other.find(token);if (ite != other.end()){return ;
// return ite->first;}else{other[token] = other.size();return ;
// return token;}
}
void error()
{cout << token << "\t-->\t该单词不存在" << endl;
}
//词法分析函数，逐个识别单词
string LexAnalyze()
{token = "";getChar();getnbc();string val;
// int num = -1;if(character>='a'&&character<='z' || character>='A'&&character<='Z'){while (letter() || digit()) //为字母或数字{concat();//追加到token末尾// if(token=="odd")
// {
// getChar();
// Three();
// return ;
// }getChar();//读取下一个字符}if(token=="odd"){getChar();Three();return 0;}retract();//回退一个字符{
// val = symbol();//查看标识符表symbol();}}else if(character>='0' && character<='9'){int flag=0;while (character>='0' && character<='9' || character>='a' && character<='z' || character>='A' && character <='Z'){if(character>='0' && character<='9')concat();if(character>='a' && character<='z' || character>='A' && character <='Z'){concat();flag=1;}getChar();}if(flag==1){error();return 0;}retract();
// val = constant();//查看常数表constant();}else if(character=='<'){concat();getChar();if (character == '='){concat();Three();
//返回<=符号}else if(character=='>'){concat();Three();}else{retract();Three();
//返回<符号}}else if(character=='>'){concat();getChar();if (character == '='){concat();Three();
//返回>=符号}else{retract();Three();
//返回>符号}}else if(character=='='){concat();getChar();if (character == '='){concat();Three();
//返回==符号}else{retract();Three();
//返回=符号}}else if(character==':'){concat();getChar();if (character == '='){concat();Three();}else{cout<<token<<endl;error();return 0;}}else if(character=='+'){concat();Three();}else if(character=='-'){concat();Three();}else if(character=='*'){concat();Three();}else if(character=='/'){concat();Three();}else if(character=='('){concat();Three();}else if(character==')'){concat();Three();}else if(character==','){concat();Three();}else if(character=='.'){concat();Three();}else if(character==';'){concat();Three();}else if(character=='#'){concat();return token;}else{error();return 0;}return token;}
void show_table()
{cout << "\n==================" << "标识符" << "==================" << endl;
// cout << "标识符\t\t类别编码\t表中位置" << endl;for (ite=Symbol.begin(); ite != Symbol.end(); ite++){
// int flag=0;
// for (int i = 0; i < len; i++)
// {
// cout<<Reserve[i]<<endl;
// if (Reserve[i] == ite->first)
// {
// cout<<ite->first<<"是保留字"<<" ";
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;
// flag=1;
// break;
// }
//
//
// }
// if(flag==0)
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);if(iter!=type.end())cout << "("<<iter->second <<","<<ite->second<<")" << endl;elsecout << "("<<type.size() <<","<<ite->second<<")" << endl;}cout << "\n==================" << "常数表" << "==================" << endl;
// cout << "常量值\t\t类别编码\t表中位置" << endl;for (ite = Digit.begin(); ite != Digit.end(); ite++){
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);
// if(iter!=type.end())
// cout << "("<<iter->second <<","<<ite->second<<")" << endl;
// elsecout << "("<<type.size()-1 <<","<<ite->second<<")" << endl;}cout << "\n==================" << "算符、界符" << "==================" << endl;for (ite = other.begin(); ite != other.end(); ite++){
// cout << "("<<ite->first <<","<<ite->second<<")" << endl;map<string,int>::iterator iter;iter=type.find(ite->first);cout << "("<<iter->second <<","<<ite->second<<")" << endl;
// cout<<iter->second<<endl;}
}
int main()
{
// clock_t start,finish;
// double totaltime;
// start=clock();type["begin"]=type.size();type["end"]=type.size();type["if"]=type.size();type["then"]=type.size();type["while"]=type.size();type["do"]=type.size();type["const"]=type.size();type["var"]=type.size();type["call"]=type.size();type["procedure"]=type.size();type["+"]=type.size();type["-"]=type.size();type["*"]=type.size();type["/"]=type.size();type["odd"]=type.size();type["="]=type.size();type["<>"]=type.size();type["<"]=type.size();type[">"]=type.size();type["<="]=type.size();type[">="]=type.size();type[":="]=type.size();type["("]=type.size();type[")"]=type.size();type[","]=type.size();type["."]=type.size();type[";"]=type.size();type["常数"]=type.size();type["标识符"]=type.size();// init_Reserve();//保留字表初始化Symbol.clear();//标识符集初始化Digit.clear();//常数集初始化index = 0;character = ' ';token = "";cout << "请输入待词法分析的源程序代码：输入文件结束符结束输入\n" << endl;//源程序代码输入处理
// instr="var a,b,c; a:=1; b:=2; c:=a+b";char ch[1000];string ins;
// printf("%d\n",gets(ch));
// printf("\n%d",&ch[1]);
// cout<<gets(ch)<<endl;while(gets(ch)){FILE *fp;
// char str[1000];map<string,int>::iterator iter;if((fp=fopen("d.txt","w"))==NULL){printf("error occur!\n");exit(1);}if((fp=fopen("d.txt","a"))==NULL){printf("error occur!\n");exit(1);}// ins=ch;instr=ch;index=0;while (index < instr.size()){char* str=(char*)LexAnalyze().data();
// fprintf(fp,"%s\n",str);
// cout<<str<<endl;if(strcmp(str,"#")==0){
// printf("*");fprintf(fp,"%s",str);}else{iter=type.find(str);if(iter!=type.end())// if(index==instr.size())fprintf(fp,"(%d,%s)\n",iter->second,str);
// else
// fprintf(fp,"(%d,%s)\n",iter->second,str);else{iter=Digit.find(str);if(iter!=Digit.end())// if(index==instr.size())fprintf(fp,"(28,%s)\n",str);
// else
// fprintf(fp,"(28,%s)\n",str);}}}fclose(fp);// cout<<instr<<endl;memset(ch,0,sizeof(ch));}yufafenxi();// cout<<instr<<endl;
// string in;
// while (cin >> in&&in != "@")
// {
// instr = instr + " " + in;
// }//识别二元组初始化
// while (index < instr.size())
// {
// LexAnalyze();
// }//展示构造的各种词汇表show_table();// finish=clock();
// totaltime=(double)(finish-start)/CLOCKS_PER_SEC;
// cout<<totaltime<<endl;
// //system("pause");return 0;}
要求实现以下效果：
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