编译原理实验指导书

编译原理实验指导湖州师范学院计算机系 2016年3月实验一 词法分析程序的设计与实现一、实验目的：加深对词法分析器工作过程的理解；加强对词法分析方法的掌握；能够采用一种编程语言实现简单的词法分析程序；能够使用自己编写的分析程序对简单的程序段进行词法分析。

二、实验内容：选择已有的一种高级语言(例如C语言)，或者自定义一种程序设计语言，编制它的词法分析程序。

词法分析程序的实现可以采用任何一种编程工具。

三、实验要求：1. 对单词的构词规则有明确的定义；2. 编写的分析程序能够正确识别源程序中的单词符号；3. 识别出的单词以<记号名，属性值>的形式保存在符号表中；4. 词法分析中源程序的输入以.c格式，分析后的符号表保存在.txt文件中。

5.*对于源程序中的词法错误，能够做出简单的错误处理，给出简单的错误提示，保证顺利完成整个源程序的词法分析；6. *实验报告要求用自动机或者文法的形式对词法定义做出详细说明，说明词法分析程序的工作过程，说明错误处理的实现。

四、实验学时：4学时五、实验步骤：1. 定义目标语言的可用符号表和构词规则；2. 依次读入源程序符号，对源程序进行单词切分和识别，直到源程序结束；3. 对正确的单词，按照它的种别以<记号名，属性值>的形式保存到符号表中；4. *对不正确的单词，做出相应的错误处理。

六、选作实验可以根据自身的情况完善词法分析程序的错误处理功能（实验要求的第5&6点），如对错误的单词给出准确的位置和错误类型提示等。

七、作业提交时间试验结束后三周内提交，提交纸质作业及可运行程序及其代码，实验报告格式参考院系的相关规定。

八、提示1. char Scanin[100],Scanout[100]; //用于接收输入输出文件名FILE *fin,*fout; //用于指向输入输出文件的指针2. //下面定义保留，为简化程序，使用字符指针数组保存所有保留字。

//如果想增加保留字，可继续添加，并修改保留字数目#define keywordSum 8char *keyword[keywordSum]={ "if","else","for","while","do","int","read","write"}; 3. //下面定义纯单分界符，如需要可添加char singleword[50]="+-*(){};,:";4. //下面定义双分界符的首字符char doubleword[10]="><=!";5. scanf("%s",Scanin);printf("请输入词法分析输出文件名（包括路径）：");scanf("%s",Scanout);6. if ((fin=fopen(Scanin,"r"))==NULL) //判断输入文件名是否正确{printf("\n打开词法分析输入文件出错!\n");return(1);//输入文件出错返回错误代码1}if ((fout=fopen(Scanout,"w"))==NULL) //判断输出文件名是否正确{printf("\n创建词法分析输出文件出错!\n");return(2); //输出文件出错返回错误代码2}7. ch=getch(fin);//读取文件里的一个字符8. isalpha(ch) //字母判断函数isnum(ch)) //数字判断函数strcmp(token,keyword[n]) //串比较fprintf(fout,"%s\t%s\n","ID",token); //输出标识符符号到fout指定的文件 strchr(singleword,ch) //声明: char *strchr( const char *string, int c );//在字符串string中搜索字符c，若成功则返回一个指向该字符第一次出现的位置，否则返回NULL//这个例子中的变量x的值为5：char string[]="hello"; char *p; int x; p=strchr(string，'o'）; x=p-string+1;九、词法分析程序参考(部分)********************************************#include <stdio.h>#include <string.h>#include <stdlib.h>void init();main(){int i;init();i=scanner();if(i==1)printf("The answer is in 'output.txt':");getch();}void init(){char *key[]={" ","auto","break","case","char","const","continue","default","do","double", "else","enum","extern","float","for","goto","if","int","long","register","return","short","signed","sizeof","static","struct","switch","typedef","union","unsigned","void","volatile","while"};char *limit[]={" ","(",")","[","]","->",".","!","++","--","&","~","*","/","%","+","-","<<",">>","<","<=",">",">=","==","!=","&&","||","=","+=","-=","*=","/=",",",";","{","}","#","_","'"};FILE *fp;int i;char c;fp=fopen("key.txt","w");for(i=1;i<=32;i++)fprintf(fp,"%s\n",key[i]);fclose(fp);fp=fopen("limit.txt","w");for(i=1;i<=38;i++)fprintf(fp,"%s\n",limit[i]);c='"';fprintf(fp,"%c\n",c);fclose(fp);fp=fopen("id.txt","w");fclose(fp);fp=fopen("constant.txt","w");fclose(fp);fp=fopen("output.txt","w");fclose(fp);}char * dtb(char *buf){int temp[20];char *binary;int value=0,i=0,j;for(i=0;buf[i]!='\0';i++)value=value*10+(buf[i]-48);if(value==0){binary=malloc(2*sizeof(char));binary[0]='0';binary[1]='\0';return(binary);}while(value!=0){temp[i++]=value%2;value/=2;}temp[i]='\0';binary=malloc((i+1)*sizeof(char));for(j=0;j<=i-1;j++)binary[j]=(char)(temp[i-j-1]+48);binary[i]='\0';return(binary);}int find(char *buf,int type,int command) {int number=0;FILE *fp;char c;char temp[30];int i=0;switch(type)case 1: fp=fopen("key.txt","r");break;case 2: fp=fopen("id.txt","r");break;case 3: fp=fopen("constant.txt","r");break;case 4: fp=fopen("limit.txt","r");}c=fgetc(fp);while(c!=EOF){while(c!='\n'){temp[i++]=c;c=fgetc(fp);}temp[i]='\0';i=0;number++;if(strcmp(temp,buf)==0){fclose(fp);return(number);}elsec=fgetc(fp);}if(command==1){fclose(fp);return(0);}switch(type){case 1: fp=fopen("key.txt","a");break;case 2: fp=fopen("id.txt","a");break;case 3: fp=fopen("constant.txt","a");break;case 4: fp=fopen("limit.txt","a");}fprintf(fp,"%s\n",buf);fclose(fp);return(number+1);}void cs_manage(char *buffer){FILE *fp;char *pointer;int result;pointer=dtb(buffer);result=find(pointer,3,2);fp=fopen("output.txt","a");fprintf(fp,"%s\t\t\t3\t\t\t%d\n",buffer,result);fclose(fp);}void ch_manage(char *buffer){FILE *fp;int result;result=find(buffer,1,1);fp=fopen("output.txt","a");if(result!=0)fprintf(fp,"%s\t\t\t1\t\t\t%d\n",buffer,result);else{result=find(buffer,2,2);fprintf(fp,"%s\t\t\t2\t\t\t%d\n",buffer,result);}fclose(fp);}void er_manage(char error,int lineno){printf("\nerror: %c ,line %d",error,lineno); }int scanner(){FILE *fpin,*fpout;char filename[20];char ch;int i=0,line=1;int count,result,errorno=0;char array[30];char *word;printf("\nInput the file name:");scanf("%s",filename);if((fpin=fopen(filename,"r"))==NULL){printf("the file you input is not exist!");getch();return 0;}ch=fgetc(fpin);while(ch!=EOF){i=0;if(((ch>='A')&&(ch<='Z'))||((ch>='a')&&(ch<='z'))||(ch=='_')){while(((ch>='A')&&(ch<='Z'))||((ch>='a')&&(ch<='z'))||(ch=='_')||((ch>='0')&&(ch<='9'))) {array[i++]=ch;ch=fgetc(fpin);}word=(char *)malloc((i+1)*sizeof(char));memcpy(word,array,i);word[i]='\0';ch_manage(word);if(ch!=EOF)fseek(fpin,-1L,SEEK_CUR);}else if(ch>='0'&&ch<='9'){while(ch>='0'&&ch<='9'){array[i++]=ch;ch=fgetc(fpin);}word=(char *)malloc((i+1)*sizeof(char));memcpy(word,array,i);word[i]='\0';cs_manage(word);if(ch!=EOF)fseek(fpin,-1L,SEEK_CUR);}else if((ch==' ')||(ch=='\t'));else if(ch=='\n')line++;else if(ch=='/'){ch=fgetc(fpin);if(ch=='='){fpout=fopen("output.txt","a");fprintf(fpout,"/=\t\t\t4\t\t\t32\n");fclose(fpout);}else if(ch!='*'){fpout=fopen("output.txt","a");fprintf(fpout,"/\t\t\t4\t\t\t13\n");fclose(fpout);fseek(fpin,-1L,SEEK_CUR);}else if(ch=='*'){count=0;ch=fgetc(fpin);while(count!=2){count=0;while(ch!='*')ch=fgetc(fpin);count++;ch=fgetc(fpin);if(ch=='/')count++;elsech=fgetc(fpin);}}}else if(ch=='"'){fpout=fopen("output.txt","a");fprintf(fpout,"%c\t\t\t4\t\t\t37\n",ch);ch=fgetc(fpin);while(ch!='"')ch=fgetc(fpin);fprintf(fpout,"%c\t\t\t4\t\t\t37\n",ch);fclose(fpout);}else{array[0]=ch;ch=fgetc(fpin);if(ch!=EOF){array[1]=ch;word=(char *)malloc(3*sizeof(char));memcpy(word,array,2);word[2]='\0';result=find(word,4,1);if(result==0){word=(char *)malloc(2*sizeof(char));memcpy(word,array,1);word[1]='\0';result=find(word,4,1);if(result==0){er_manage(array[0],line);errorno++;fseek(fpin,-1L,SEEK_CUR);}else{fpout=fopen("output.txt","a");fprintf(fpout,"%s\t\t\t4\t\t\t%d\t\n",word,result);fclose(fpout);fseek(fpin,-1L,SEEK_CUR);}}else{fpout=fopen("output.txt","a");fprintf(fpout,"%s\t\t\t4\t\t\t%d\n",word,result);fclose(fpout);}}else{word=(char *)malloc(2*sizeof(char));memcpy(word,array,1);word[1]='\0';result=find(word,4,1);if(result==0)er_manage(array[0],line);else{fpout=fopen("output.txt","a");fprintf(fpout,"%s\t\t\t4\t\t\t%d\n",word,result);fclose(fpout);}}}ch=fgetc(fpin);}fclose(fpin);printf("\nThere are %d error(s).\n",errorno);return 1;}实验二 语法分析器的设计与实现一、实验目的：加深对语法分析器工作过程的理解；加强对递归下降法实现语法分析程序的掌握；能够采用一种编程语言实现简单的语法分析程序；能够使用自己编写的分析程序对简单的程序段进行语法翻译。