一个词法分析器的问题
#include<ctype.h>#include<stdio.h>
#include<string.h>
#include<malloc.h>
#define N sizeof(struct keyword)
char token[20];
struct keyword
{
char str[20];
struct keyword *next;
};
struct keyword *creatkt(void)
{
struct keyword *p1,*p2,*head;
head=p1=p2=(struct keyword *)malloc(N);
printf("请输入关键字:");
scanf("%s",&p2->str);
while(strcmp(p2->str,"end"))
{
p2=(struct keyword *)malloc(N);
p1->next=p2;
p1=p2;
scanf("%s",&p2->str);
}
p2->next=NULL;
return head;
}
int lookup(struct keyword *p)
{
int flag=0;
while(p)
{
if(strcmp(p->str,token))
{
p=p->next;
}
else
{
flag=1;
p=NULL;
}
}
return flag;
}
void scanner(FILE *fp1,FILE *fp2,struct keyword *p)
{
int i,c;
char ch;
char s[20]={"标识符"},t[20]={"关键字"},u[20]={"数字"},v[20]={"符号"},w[20]={"出错"};
ch=fgetc(fp1);
if('a'<ch<'z'||'A'<ch<'Z')
{
token[0]=ch;
ch=fgetc(fp1);
i=1;
while('a'<ch<'z'||'A'<ch<'Z'||'0'<ch<'9')
{
token[i]=ch;
i++;
ch=fgetc(fp1);
}
token[i]='\0';
fseek(fp1,-1,1);
c=lookup(p);
if(c==0)
{
fprintf(fp2,"%s,%s\n",s,token);
}
else
{
fprintf(fp2,"%s,%s\n",t,token);
}
}
else if('0'<ch<'9')
{
token[0]=ch;
ch=fgetc(fp1);
i=1;
while('0'<ch<'9')
{
token[i]=ch;
i++;
ch=fgetc(fp1);
}
token[i]='\0';
fseek(fp1,-1,1);
fprintf(fp2,"%s,%s\n",u,token);
}
else
switch(ch)
{
case'<':ch=fgetc(fp1);
if(ch=='=')
{
fprintf(fp2,"%s,%s\n",v,token);
}
else if(ch=='>')
{
fprintf(fp2,"%s,%s\n",v,token);
}
else
{
fseek(fp1,-1,1);
fprintf(fp2,"%s,%s\n",v,token);
}
break;
case'=':
fprintf(fp2,"%s,%s\n",v,token);
break;
case'>':ch=fgetc(fp1);
if(ch=='=')
{
fprintf(fp2,"%s,%s\n",v,token);
}
else
{
fseek(fp1,-1,1);
fprintf(fp2,"%s,%s\n",v,token);
}
break;
default:
fprintf(fp2,"%s,%s\n",w,token);
break;
}
fclose(fp2);
}
void main()
{
FILE *fp1,*fp2;
struct keyword *p;
p=(struct keyword *)malloc(N);
p=creatkt();
if((fp1=fopen("d:\\zjm1.txt","rt"))==NULL)
{
printf("\n不能打开此文件,按任意键退出!");
getchar();
}
if((fp1=fopen("d:\\zjm.txt","wt"))==NULL)
{
printf("\n不能打开此文件,按任意键退出!");
getchar();
}
while(!feof(fp1))
scanner(fp1,fp2,p);
fclose(fp1);
fclose(fp2);
}
这是一个简单词法分析器的程序，想问问大家为什么编译时总提示错误进不了sanner()函数！！！
