#include<stdio.h>
#include<stdlib.h>
#include<string.h>
struct student
{
int num;
char name[20];
int score;
}t;
int main()
{
FILE *fp;
fp=fopen("student.dat","rb+");
if(!fp) exit(0);
char name[20];
puts("请输入查找的学生姓名：");
gets(name);
int low,n,high,mid;
fseek(fp,0,2);//指针定位在文件末
n=ftell(fp)/sizeof(t);
low=0;
high=n-1;
while(low<=high)
{
mid=(low+high)/2;
fseek(fp,mid *sizeof(t),0);
fread(&t,sizeof(t),1,fp);
if(strcmp(t.name,name)==0)
{
puts("find");
t.score=88;
fseek(fp,-sizeof(t),1);//回跳
fwrite(&t,sizeof(t),1,fp);
break;
}
else if(strcmp(t.name,name)>0)
{
high= mid-1;
}
else
{
low=mid+1;
}
}
if(low>high)
puts("no find");
rewind(fp);//回到文件头
while(fread(&t,sizeof(t),1,fp))//检验是否操作成功
{
printf("%d %s %d\n",t.num ,t.name ,t.score );
}
fclose(fp);
return 0;
}
