编译原理自顶向下语法分析方法的实现

1、实 验 报 告实验项目列表序号实验项目名称成绩01DFA的生成与字符串的识别02程序段的单词识别03自顶向下语法分析方法的实现04050607080910111213141516总评成绩： 教员签字：一、 实验名称自顶向下语法分析方法的实现二、实验目的1.掌握自顶向下语法分析的方法； 2.运用编程的手段实现自顶向下语法分析。三、实验内容和要求四、实验环境1硬件环境：PC机2软件环境：Windows操作系统，VC+集成开发环境五、算法设计思想六、主要问题与解决方法七、实验结果以下是程序的用户运行界面截图：八、体会、质疑、建议九、源代码 #include<fstream>#includ

2、e<sstream>#include<iostream>#include<vector>#include<string>#include<windows.h>#include<iterator>#include<algorithm>#include<stdlib.h>#define M 20using namespace std;void gotoxy(int x,int y)COORD coord;coord.X=x;coord.Y=y;SetConsoleCursorPosition( GetS

3、tdHandle( STD_OUTPUT_HANDLE ), coord );class tablepublic:void read();friend class an_process;string find_str(char row,char col);private:string matrixMM;char start;vector<string> vec_row;vector<string> vec_col;class sentencepublic:void read_in();friend class an_process;private:string str_

4、input;class an_processpublic:void analyse(const table LL1_table,const sentence input);void write_result();void print2(int x,int y);private:vector<int> step;vector<vector<char> > stack_note;vector<string> remain;vector<string> production;void table:read()string a,str;cha

5、r x,y;int linenum = 0;char line1024=0;ifstream infile("table1.txt");if(!infile)cerr<<"错误！无法存储用户数据！n"while(infile.getline(line,sizeof(line)stringstream word(line);if(linenum>1)if(word>>x&&word>>y&&word>>str)matrixx-48y-48=str;/*cout<&l

6、t;x<<" "cout<<y<<" "cout<<matrixx-48y-48<<" "*/while(word>>a&&linenum<2)if(linenum=0)vec_col.push_back(a);/*cout<<a<<" "*/else if(linenum=1)vec_row.push_back(a);/*cout<<a<<" "*/*c

7、out<<endl;*/linenum+;start=vec_col00;/*for(int icnt=0;icnt<vec_col.size();icnt+)cout<<vec_colicnt<<" "*/string table:find_str(char row,char col)for(int x=0;x<vec_col.size();x+)for(int y=0;y<vec_row.size();y+)if(row=vec_colx0&&col=vec_rowy0)return matrixx+

8、1y+1;return ""void an_process:analyse(table LL1_table,sentence input)int icnt=0,jcnt=0,kcnt;string ac,prod="",re=""vector<char> stack;char Now_word=input.str_inputicnt;char NOW_state=LL1_table.start;string:const_iterator Eiter;string:const_iterator Biter;stack.pus

9、h_back('#');stack.push_back(NOW_state);for(;icnt<input.str_input.size();)step.push_back(+jcnt);stack_note.push_back(stack);for(kcnt=icnt;kcnt<input.str_input.size();kcnt+)re=re+input.str_inputkcnt;re=re+"#"remain.push_back(re);re.erase();Now_word=input.str_inputicnt;NOW_state

10、=stack.back();if(NOW_state=Now_word)stack.erase(stack.end()-1);icnt+;production.push_back("(匹配)");elseac=LL1_table.find_str(NOW_state,Now_word);Biter=ac.begin();Biter-;Eiter=ac.end();Eiter-;if(ac="")prod=prod+NOW_state;prod=prod+""prod=prod+""stack.erase(stack

11、.end()-1);production.push_back(prod);prod.erase();else if(ac!="")stack.erase(stack.end()-1);prod.empty();prod=prod+NOW_state;prod=prod+""+ac;production.push_back(prod);prod.erase();for(;Eiter!=Biter;Eiter-)stack.push_back(*Eiter);else cout<<"分析失败n"exit(0);if(stack

12、.size()!=1|stack.back()!='#')cout<<"分析失败n"exit(0);void an_process:write_result()step.push_back(step.back()+1);vector<char> a;a.push_back('#');stack_note.push_back(a);remain.push_back("#");production.push_back("接受");gotoxy(27,1);cout<<&q

13、uot;输入串"<<'"'<<remain0;cout<<"b"<<'"'<<"的分析过程"<<endl<<endl;print2(step.size()+1,4);vector<int>:const_iterator iter1=step.begin();vector<vector<char> >:const_iterator iter2=stack_note.begin(

14、);vector<string>:const_iterator iter3=remain.begin();vector<string>:const_iterator iter4=production.begin();gotoxy(8,4);cout<<"步骤"gotoxy(27,4);cout<<"分析栈"gotoxy(44,4);cout<<"剩余输入串"gotoxy(63,4);cout<<"所用产生式"for(int xy=0;iter1

15、!=step.end();iter1+)gotoxy(9,xy+6);cout<<(*iter1);xy=xy+2;for(xy=0;iter2!=stack_note.end();iter2+)gotoxy(27,xy+6);for(int icnt=0;icnt<(*iter2).size();icnt+)cout<<(*iter2)icnt;xy=xy+2;for(xy=0;iter3!=remain.end();iter3+)gotoxy(44,xy+6);cout<<(*iter3);xy=xy+2;for(xy=0;iter4!=produ

16、ction.end();iter4+)gotoxy(63,xy+6);cout<<(*iter4);xy=xy+2;cout<<endl<<endl;void an_process:print2(int x,int y)/简易画线代码，呵呵,画行直线int i,j;for(int icnt=0;icnt<y-1;icnt+)for(i=0;i<37/y;i+)printf("");printf("");for(i=0;i<37/y;i+)printf("");putchar(10)

17、;for(icnt=0;icnt<y-1;icnt+)for(i=0;i<37/y;i+)printf(" ");printf("");putchar(10);for(j=0;j<x-1;j+)/画5行直线for(icnt=0;icnt<y-1;icnt+)for(i=0;i<37/y;i+)printf("");printf("");for(i=0;i<37/y;i+)printf("");putchar(10);for(icnt=0;icnt<y-1;icnt+)for(i=0;i<37/y;i+)printf(" ");printf("");putchar(10);for(icnt=0;icnt<y-1;icnt+)for(i=0;i<37/y;i+)printf("");printf("");for(i=0;i<