c语言信息管理系统中删除功能中fseek(fp,a,0);是什么意思 功能是什么？？？求高手帮忙

Question

void delete()
{
int m,k=0;
long a,b;
char namekey[8], valid[4];
printf("\n请输入您要删除的职工姓名:");
scanf("%s",namekey);
if((fp=fopen("worker.xls","r+"))==NULL)
{
printf("\n不能打开该文件！");
exit();
}
while(!feof(fp))
{
a=ftell(fp);
fscanf(fp,"%s%s%s%s%s%s%s%s%s\n",one.name,one.num,one.sex,one.age,one.record,one.position,one.wanges,one.tel,one.addr);
if(strcmp(namekey,one.name)==0)
{
k=1;
break;
}
}
if(k==1)
{
printf("\n已查到，记录为");
printf("\n%-10s%-8s%-5s%-5s%-10s%-8s%-8s%-10s%-15s\n",one.name,one.num,one.sex,one.age,one.record,one.position,one.wanges,one.tel,one.addr);
printf("\n确实要删除,按1；不删除，按0：");
scanf("%d",&m);
if(m==1)
{
fseek(fp,a,0);
fprintf(fp,"%-10s%-8s%-5s%-5s%-10s%-8s%-8s%-10s%-15s\n" "","","","","","","","","");
}
}
else
printf("\n对不起，查无此人。");
fclose(fp);
}
谢你的回答 追问一下fseek(fp,a,0)中的“0”是什么意思啊 还有为什么有赋值a=ftell(fp);意义是什么 有追分

Answer 1

int fseek( FILE *stream, long offset, int origin );
第一个参数stream为文件指针
第二个参数offset为偏移量，正数表示正向偏移，负数表示负向偏移
第三个参数origin设定从文件的哪里开始偏移
fseek(fp,a,0)就是把文件指针fp从文件头偏移a个字节的位置