主题：跪求词法扫描器
gavinioro
[专家分：0] 发布于 2006-10-23 10:44:00
本人欲作一个词法扫描器希望有贤士能够相助！
程序设计要求：
1.可以从输入的SIMPLE语言源程序中,识别出各个具有独立意义的单词,即保留字,标识符,常数,运算符,界限符五大类;
2.提供程序输入界面;
3.词法后可查看符号表和TOKEN串表;
4.保存符号表和TOKEN串表(如:文本文件)
5.遇到错误时可显示提示信息,然后跳过错误部分继续进行分析.
马上就要交作业了!!我还是做不出来!!哪位有符合我的要求的源文件希望帮帮小弟!!
急死我了T T
我的QQ14769377,邮箱ghostcry1314@21cn.com
哪位能帮助下我真是不胜感激!!先谢谢各位了!
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colina [专家分：0] 发布于 2006-10-25 21:46:00
#include <process.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <malloc.h>
#include <ctype.h>
#include <conio.h>
FILE *fp;
char ch;
char *keyword[]={"do","begin","if","else","for","while","int","char","float","double"};
char *limit[]={",",";","(",")","{","}","()"};
char *process[]={"+","-","*","/","<","<=","=",">",">=","!=",":=",".","&","&&","%","_"} ;
char bsfb[100][20];
char numb[100][20];
static int countb=0;
int search(char a[],int type)
{
int i;
switch (type)
{
case 0:
for(i=0;i<10;i++)
{
if(strcmp(keyword[i],a)==0)
return(1);
}
break;
case 1:
for(i=0;i<7;i++)
{
if(strcmp(limit[i],a)==0)
return(1);
}
break;
case 2:
for(i=0;i<16;i++)
{
if(strcmp(process[i],a)==0)
return(1);
}
break;
}
return(0);
}
char letterprocess (char ch)
{
int i=0;
char letter[20];
while ((isalnum(ch)!=0)||(ch=='_'))
{
letter[i++]=ch;
ch=fgetc(fp);
};
letter[i]='\0';
if (search(letter,0))
{
printf(" < ±£Áô×Ö %s >\n",letter);
}
else
{
printf(" < ±êʶ·û %s >\n",letter);
strcpy(bsfb[countb++],letter);
}
return(ch);
}
char numberprocess(char ch)
{
int i=0;
char num[20];
while((isdigit(ch)!=0)||(ch=='.'))
{
num[i++]=ch;
ch=fgetc(fp);
}
if(isalpha(ch)!=0)
{
while(isspace(ch)==0)
{
num[i++]=ch;
ch=fgetc(fp);
}
num[i]='\0';
printf(" < ·Ç·¨±êʶ·û %s >\n",num);
return(ch);
}
num[i]='\0';
printf(" < Êý×Ö %s >\n",num);
return(ch);
}
char otherprocess(char ch)
{
int i=0;
char other[20];
if (isspace(ch)!=0)
{
ch=fgetc(fp);
return (ch);
}
while ((isspace(ch)==0)&&(isalnum(ch)==0))
{
other[i++]=ch;
ch=fgetc(fp);
}
other[i]='\0';
if (search(other,1))
printf(" < ½ç·û %s >\n",other);
else
if (search(other,2))
printf(" < ÔËËã·û %s >\n",other);
else
printf(" < ·Ç·¨×Ö·û %s >\n",other);
return (ch);
}
void main ()
{
char str,c;
int i=0;
printf("**********************************´Ê·¨·ÖÎöÆ÷************************************\n");
printf("\n");
printf("---------------------------------·ÖÎö½á¹û-------------------------------\n");
printf("\n");
if ((fp=fopen("1.txt","r"))==NULL)
printf("ÎÞ·¨´ò¿ªÎļþ£¡\n");
else
{
str =fgetc(fp);
while (str!=EOF)
{
if ((isalpha(str)!=0)||(str=='_'))
str=letterprocess(str);
else
{
if (isdigit(str)!=0)
str=numberprocess(str);
else
str=otherprocess(str);
}
};
printf("\n");
for(i=0;i<countb;i++)
{
printf("%s\n",bsfb[i]);
}
}
c=getch();
}
后来改的老师检查完了就找不到了
这个也不是很全面，你可以自己改改
[em1][em1][em1]
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