词法分析器文档

1、词法分析程序文档说明：该词法分析器实现对C语言源代码进行词法分析的功能，由文件输入，将输入的源代码输出为token序列，用二元组形式由文件和屏幕输出，文件输出首先输入源文件路径和文件名称，将注释过滤，能够报告不合法字符，并且记录源代码的行数，单词数（包括关键字，标识符和常量）和字符数(包括字母，数字，标点符号，运算符，空格和换行符)。程序设计：具体见源代码源代码：#include <stdio.h>#include <string>#include <iostream>#include <cstdlib>using namespace std;#

2、define MAX 32char ch =' 'int line=1,zifu=1,word=0;/*line记录行数zifu记录字符数(包括字母，数字，标点符号，运算符，空格和换行符)word记录单词数（包括关键字，标识符和常量）*/ string key32= "auto","break","case","char","const","continue","default","do","double&qu

3、ot;, "else","enum","extern","float","for","goto","if","int","long","register", "return","short","signed","sizeof","static","struct","sw

4、itch","typedef", "union","unsigned","void","volatile","while" ;/c语言中的所有关键字int Iskey(string c) /关键字判断 int i; for(i=0; i<MAX; i+) if(pare(c)=0) /将字符串与关键字一一进行比较 return 1; return 0;int IsLetter(char c) /判断是否为字母 if(c<='z&#

5、39;)&&(c>='a')|(c<='Z')&&(c>='A') return 1; else return 0;int IsDigit(char c) /判断是否为数字 if(c>='0'&&c<='9') return 1; else return 0;void analyse(FILE *fpin,FILE *fpout) string arr=""string str="" while(c

6、h=fgetc(fpin)!=EOF) zifu+;/将文件中的字符逐一进行扫描，包括字母，数字，标点符号，运算符，空格和换行符 arr="" if(IsLetter(ch)/对开头是字母或数字的字符串进行判断 while(IsLetter(ch)|IsDigit(ch)|ch='_')/符合标识符或者关键字标准的字符串进行判断 if(ch<='Z')&&(ch>='A') ch=ch+32; arr=arr+ch;/将每个单个读取的字符连成字符串 ch=fgetc(fpin); fseek(fpi

7、n,-1L,SEEK_CUR);/不满足条件的多读取的字符回退一格 if (Iskey(arr)/判断字符串是否是关键字 fprintf(fpout,"(%s %s)n",arr.c_str(),"key"); printf("(%s %s)n",arr.c_str(),"key");word+; else/字符串不是关键字则判定为标识符 fprintf(fpout,"(%s %s)n",arr.c_str(),"id"); printf("(%s %s)n&quo

8、t;,arr.c_str(),"id");word+; else if(IsDigit(ch)/开头为数字的串即为常量 while(IsDigit(ch)|ch='.'&&IsDigit(fgetc(fpin) arr=arr+ch; ch=fgetc(fpin); fseek(fpin,-1L,SEEK_CUR); fprintf(fpout,"(%s %s)n",arr.c_str(),"num"); printf("(%s %s)n",arr.c_str(),"num

9、");word+; else switch(ch)/既不是数字也不是字母的符号判定 case'+': ch=fgetc(fpin);/判定+，+=，+ if(ch='+') fprintf(fpout,"(%s %s)n","+","-"); printf("(%s %s)n","+","-");zifu+; if(ch='=') fprintf(fpout,"(%s %s)n","+=&

10、quot;,"-"); printf("(%s %s)n","+=","-");zifu+; else fprintf(fpout,"(%s %s)n","+","-"); printf("(%s %s)n","+","-"); fseek(fpin,-1L,SEEK_CUR); break; case'-' : ch=fgetc(fpin); if(ch='-')

11、/判定-，-=，- fprintf(fpout,"(%s %s)n","-","-"); printf("(%s %s)n","-","-");zifu+; if(ch='=') fprintf(fpout,"(%s %s)n","-=","-"); printf("(%s %s)n","-=","-");zifu+; else fprint

12、f(fpout,"(%s %s)n","-","-"); printf("(%s %s)n","-","-"); fseek(fpin,-1L,SEEK_CUR); break; case'*' : fprintf(fpout,"(%s %s)n","*","-"); printf("(%s %s)n","*","-"); break; ca

13、se'=' : ch=fgetc(fpin);/判定=，= if(ch='=') fprintf(fpout,"(%s %s)n","=","-"); printf("(%s %s)n","=","-");zifu+; else fprintf(fpout,"(%s %s)n","=","EQ"); printf("(%s %s)n","=",&

14、quot;EQ"); fseek(fpin,-1L,SEEK_CUR); break; case'/' : ch=fgetc(fpin);/判定是注释还是运算符/ if(ch='*')/形如/* */的注释，将注释过滤 zifu-; ch=fgetc(fpin); while(ch!='*')&&(ch=fgetc(fpin)='/') ; else if(ch='/')/形如/的注释，将注释过滤 zifu-; ch=fgetc(fpin); while(ch!='n')

15、ch=fgetc(fpin);line+; else fprintf(fpout,"(%s %s)n","/","-"); printf("(%s %s)n","/","-"); fseek(fpin,-1L,SEEK_CUR); break; case '%': fprintf(fpout,"(%s %s)n","%","-"); printf("(%s %s)n","

16、%","-"); break; case '#': fprintf(fpout,"(%s %s)n","#","-"); printf("(%s %s)n","#","-"); break; case '!': ch=fgetc(fpin);/判定！=还是！ if(ch='=') fprintf(fpout,"(%s %s)n","!=","-&qu

17、ot;); printf("(%s %s)n","!=","-");zifu+; else fprintf(fpout,"(%s %s)n","!","-"); printf("(%s %s)n","!","-"); fseek(fpin,-1L,SEEK_CUR); break; case '|': ch=fgetc(fpin); if(ch='|')/判定|还是| fprintf(

18、fpout,"(%s %s)n","|","-"); printf("(%s %s)n","|","-");zifu+; else fprintf(fpout,"(%s %s)n","|","-"); printf("(%s %s)n","|","-"); fseek(fpin,-1L,SEEK_CUR); break; case '&

19、9;: ch=fgetc(fpin); if(ch='&')/判定&&还是& fprintf(fpout,"(%s %s)n","&&","-"); printf("(%s %s)n","&&","-");zifu+; else fprintf(fpout,"(%s %s)n","&","-"); printf("(%s

20、 %s)n","&","-"); fseek(fpin,-1L,SEEK_CUR); break; case'(' : fprintf(fpout,"(%s %s)n","(","-"); printf("(%s %s)n","(","-"); break; case')' : fprintf(fpout,"(%s %s)n",")","

21、-"); printf("(%s %s)n",")","-"); break; case'' : fprintf(fpout,"(%s %s)n","","-"); printf("(%s %s)n","","-"); break; case'' : fprintf(fpout,"(%s %s)n","","-");

22、 printf("(%s %s)n","","-"); break; case'' : fprintf(fpout,"(%s %s)n","","-"); printf("(%s %s)n","","-"); break; case'.' : fprintf(fpout,"(%s %s)n",".","-"); printf(

23、"(%s %s)n",".","-"); break; case',' : fprintf(fpout,"(%s %s)n",",","-"); printf("(%s %s)n",",","-"); break; case'' : fprintf(fpout,"(%s %s)n","","-"); printf("

24、(%s %s)n","","-"); break; case'' : fprintf(fpout,"(%s %s)n","","-"); printf("(%s %s)n","","-"); break; case '"':fprintf(fpout,"(%s %s)n","引号","-"); printf("(%s

25、 %s)n","引号","-"); break; case '?': fprintf(fpout,"(%s %s)n","?","-"); printf("(%s %s)n","?","-"); break; case':' : fprintf(fpout,"(%s %s)n",":","-"); printf("(%s %s

26、)n",":","-"); break; case'>' : ch=fgetc(fpin); if(ch='=')/判定>=还是> fprintf(fpout,"(%s %s)n",">=","GE"); printf("(%s %s)n",">=","GE");zifu+; else fprintf(fpout,"(%s %s)n","

27、;>","GT"); printf("(%s %s)n",">","GT"); fseek(fpin,-1L,SEEK_CUR); break; case'<' : ch=fgetc(fpin);/判定<=还是<还是<> if(ch='=') fprintf(fpout,"(%s %s)n","<=","LE"); printf("(%s %s)n","<=","LE"); zifu+; else if(ch='>') fprintf(fpout,"(%s %s)n","<>","NE"); printf("(%s %s)n","<>","NE"); zifu+; else