北邮大三上_编译原理_词法分析实验报告

1、编译原理第三章词法分析班级：2009211311 学号姓名：schnee目录1 .实验题目和要求 32 .检测代码分析3.43 .源代码1 .实验题目和要求题目：词法分析程序的设计与实现。实验内容：设计并实现 C语言的词法分析程序，要求如下。(1)、可以识别出用 C语言编写的源程序中的每个单词符号，并以记号的形式输出每个单词符号。(2)、可以识别并读取源程序中的注释。(3)、可以统计源程序汇总的语句行数、单词个数和字符个数，其中标点和空格不计算为单词，并输出统计结果(4)、检查源程序中存在的错误，并可以报告错误所在的行列位置。(5)、发现源程序中存在的错误后，进行适当的恢复，使词法分析可以继续

2、进行，通过一次词法分析处理, 可以检查并报告源程序中存在的所有错误。实验要求：方法1 :采用C/C+作为实现语言，手工编写词法分析程序。方法2:通过编写LEX源程序，利用LEX软件工具自动生成词法分析程序。2 .检测代码分析1、H ello World 简单程序输入：CoiTipiler.cpp a.cpp x#irLclude<cstdio>firLclude-ciostreain>- frincrlude<cstdl£b>#irLcliide<c3l:rirLg>using name space 3dtei; int ma i n()pr

3、intf CrtUello Woxld 1 nTi);return 0;2、较复杂程序输入:Compilaf.cpp a.cpp x#included cstdio> 4 include<io9tieani> T i TLclude- cstcili kr- 4 include<c3tring> us Ing nairuespace std; 11n.七 main ()B(1 口七日/ b;运算符检差 a = 10; b = 1; b +;a.;a : intId b +; a /= b; a '+= 1; a -= 1; while ia 1=() /注

4、释检盍/f J.sfj osidfn Isnf/sofn*/1 printf (11 He Ila Warldl n");re-t-u.ru 二；3.异常程序输入检测Ccmpiler.cpp a.cppfr£rLclade<cstd£o>#inGlude<iG>5tKeanL>#include<c3tdlib>ini main()日 ，- 5t a;printf ("Hello World! n,T);S*return Q;三，源代码#include <cmath> #include <ccty

5、pe>#include <string>#include <vector>#include <cstdio>#include <cstdlib>#include <cstring>#include <fstream>#include <iostream>#include <algorithm>using namespace std;const int FILENAME=105;const int MAXBUF=82;const int L_END=40;const int R_END=81;c

6、onst int START=0;vector<string> Key;class funtionpublic:/ 变量声明char filenameFILENAME;ifstream f_in;char bufferMAXBUF;int l_end, r_end, forward;bool l_has, r_has;/ 开始指针/C 保留的关键字表/ 词法分析结构/ 需要词法分析的代码文件名/ 输入缓冲区/ 左半区终点，右半区终点，前进指针，/ 辅助标记位，表示是否已经填充过缓冲区vector<string> Id;/ 标识符表char C;/ 当前读入的字符/ 行数

7、，单词数，字符数/ 存放当前的字符串int linenum, wordnum, charnum;string curword;/ 函数声明void get_char();void get_nbc();void retract();void initial();void fillBuffer(int pos);void analyzer();void token_table();void note_print();void count_number();void error_report();void solve(char* file);/ 从输入缓冲区读一个字符，放入C 中， forward

8、指向下一个/ 检查当前字符是否为空字符，反复调用直到非空/ 向前指针后退一位/ 初始化要词法分析的文件/ 填充缓冲区，0 表示左 ,1 表示右/ 词法分析/ 以记号的形式输出每个单词符号/ 识别并读取源程序中的注释/ 统计源程序汇总的语句行数、单词个数和字符个数/ 检查并报告源程序中存在的所有错误/ 主调用函数void welcome()printf("n*n");*n");printf( "*Welcome to use LexicalAnalyzer*n");printf(”*nnn");void initKey()Key.cle

9、ar();Key.push_back("auto");Key.push_back("char");Key.push_back("const");Key.push_back("do");Key.push_back("break");Key.push_back("case");Key.push_back("continue");Key.push_back("default");printf( "*By schnee BUPTDat

10、e: 2011/20/10Key.push_back("double");Key.push_back("else");Key.push_back("enum");Key.push_back("extern");Key.push_back("float");Key.push_back("if");Key.push_back("int");Key.push_back("for");Key.push_back("goto"

11、);Key.push_back("long");Key.push_back("register");Key.push_back("return");Key.push_back("static");Key.push_back("short");Key.push_back("signed");Key.push_back("sizeof");Key.push_back("typedef");Key.push_back("struct

12、");Key.push_back("switch");Key.push_back("union");Key.push_back("unsigned");Key.push_back("void");Key.push_back("volatile");Key.push_back("while"); void funtion:get_char()C=bufferforward;if(C=EOF)return ;/ 结束if(C='n')linenum+;/

13、 统计行数和字符数else if(isalnum(C) charnum+;forward+;if(bufferforward=EOF)if(forward=l_end)fillBuffer(1);forward+;else if(forward=r_end) fillBuffer(0);forward=START;void funtion:get_nbc()while(C=' ' | C='n' | C='t' | C='0') get_char();void funtion:initial(char* file)Id.clear

14、();/ 清空标识符表l_end=L_END;r_end=R_END;/ 初始化缓冲区forward=0;l_has=r_has=false;bufferl_end=bufferr_end=EOF;fillBuffer(0);linenum=wordnum=charnum=0;/ 初始化行数，单词数，字符数void funtion:fillBuffer(int pos)if(pos=0)/ 填充缓冲区的左半边if(l_has=false)fin.read(buffer, l_end);if(fin.gcount()!=l_end)bufferfin.gcount()=EOF;else l_ha

15、s=false;else / 填充缓冲区的右半边if(r_has=false)fin.read(buffer+l_end+1, l_end);if(fin.gcount()!=l_end)bufferfin.gcount()+l_end+1=EOF;else r_has=false;void funtion:retract()if(forward=0)l_has=true;/ 表示已经读取过文件，避免下次再次读取forward=l_end-1;elseforward-;if(forward=l_end)r_add=true;forward-;void funtion:analyzer()FIL

16、E *token_file, *note_file, *count_file, *error_file;token_file=fopen("token_file.txt", "w");note_file=fopen("note_file.txt", "w");count_file=fopen("count_file.txt", "w");error_file=fopen("error_file.txt", "w");int i;curw

17、ord.clear();get_char();get_nbc();if(C=EOF)return false;if(isalpha(C) | C='_')/ 关键字和标识符的处理，以字母或下划线开头curword.clear();while(isalnum(C) | C='_')curword.push_back(C);get_char();retract();wordnum+;Id.push_back(curword);for(i=0; i<Key.size(); i+)if(Keyi=curword)break;/ 输出每一个单词的标识符if(i<

18、;Key.size() / 关键字fprintf(token_file, "%8d%20s%sn", wordnum, "KEY WORD", curword);elsefprintf(token_file, "%8d%20s%sn", wordnum, "Identifier", curword);else if(isdigit(C)/ 无符号数的处理curword.clear();while(isdigit(C)curword.push_back(C);get_char();if(C='.' |

19、 C='E' | C='e')/处理小数和指数形式curword.push_back(C);get_char();while(isdigit()curword.push_back(C);get_char();retract();wordnum+;Id.push_back(curword);fprintf(token_file, "%8d%20s%sn", wordnum, "Unsigned Number", curword);else if(C='#')/ 过滤掉以#开头的预处理fprintf(note_

20、file, "preproccessLine %d : ", linenum);get_char();fprintf(note_file, "%c", C);while(C!='n')get_char();fprintf(note_file, "%c", C);fprintf(note_file, "%c", C);else if(C='"')/"" 内的句子当成整个串保存起来curword.clear();get_char();while(C!=

21、9;"')curword.push_back(C);get_char();fprintf(token_file, "*string in ""%sn", curword);else if(C='/')get_char();if(C='/')/ 过滤掉 / 开头的行注释fprintf(note_file, "single-line noteLine %d : ", linenum);get_char();curword.clear();while(C!='n')curwo

22、rd.push_back(C);get_char();fprintf(note_file, "%sn", curword);else if(C='*')/ 过滤掉 /*/ 之间的段注释fprintf(note_file, "paragraph noteLine %d : ", linenum);get_char();while(true)while(C!='/')fprintf(note_file, "%c", C);get_char();get_char();if(C='*')fpri

23、ntf(note_file, "nto Line %dn", linenum);break;fprintf(note_file, "%c", C);else if(C='=')fprintf(token_file, "*ASSIGN-OP, DIVn");elsefprintf(token_file, "*CAL-OP, DIVn"); retract(); / 处理各种比较，赋值，运算符号else if(C='<')get_char();if(C='=')fp

24、rintf(token_file, "*RELOP, LEn");elsefprintf(token_file, "*RELOP, LTn");retract();else if(C='>')get_char();if(C='=')fprintf(token_file, "*RELOP, GEn"); elsefprintf(token_file, "*RELOP, GTn");retract();else if(C='=')get_char();if(C=&#

25、39;=')fprintf(token_file, "*RELOP, EQn");elsefprintf(token_file, "*ASSIGN-OP, EASYn");retract();else if(C='+')get_char();if(C='=')fprintf(token_file, "*ASSIGN-OP, ADDn"); elsefprintf(token_file, "*CAL-OP, ADDn");retract();else if(C='-&#

26、39;)get_char();if(C='=')fprintf(token_file, "*ASSIGN-OP, SUBn"); elsefprintf(token_file, "*CAL-OP, SUBn");retract();else if(C='*')get_char();if(C='=')fprintf(token_file, "*ASSIGN-OP, MULn"); elsefprintf(token_file, "*CAL-OP, MULn");retr

27、act();else if(C='!')get_char();if(C='=')fprintf(token_file, "*RELOP, UEn");else if(!isalpha(C) && C!='_')fprintf(error_file, "Line %d:error:'!' was illegal char n", linenum);else if(C=':' | C='(' | C=')' | C='

28、9; | C='' | C='' | C=',')fprintf(token_file, "*Other char%cn", C);elsefprintf(error_file, "Line %d:error:'%c' was illegal char n", linenum, C);fprintf(count_file, "The Line number is %dn", linenum);fprintf(count_file, "The word numbe

29、r is %dn", wordnum);fprintf(count_file, "The char number is %dn", charnum);fclose(token_file);fclose(note_file);fclose(count_file);fclose(error_file);void funtion:token_table()fin.open("token_file.txt");printf("The token_table is as following:n");char str1;while(1)

30、fin.read(str, 1);if(str0!=EOF)printf("%c", str0);void funtion:note_print()fin.open("note_file.txt");printf("The note is as following:n");char str1;while(1)fin.read(str, 1);if(str0!=EOF)printf("%c", str0);void funtion:count_number()fin.open("count_file.txt

31、");printf("The count result is as following:n");char str1;while(1)fin.read(str, 1);if(str0!=EOF)printf("%c", str0);void funtion:error_report()fin.open("error_file.txt");printf("The error report is as following:n");char str1;while(1)fin.read(str, 1);if(str0!=EOF)printf("%c", str0);void funtion:solve(char* file)filename=file;fin.open(filename