C语言-文件块操作

#include <stdio.h>
#include <stdlib.h>
#define FILENAME "E:\FUSHI\students.txt"

struct student
{
    int num;//学号
    char name[20];//姓名
    char rank; //成绩等级
    int score;//成绩
};

int main()
{
    FILE *fp;
    struct student stu;
    fp=fopen(FILENAME,"wb");
    if(fp==NULL)
    {
        printf("不能打开文件：%s
",FILENAME);
        exit(1);
    }
    printf("请输入学生的学号、姓名、成绩：
");
    scanf("%d",&stu.num);
    while(stu.num!=0)
    {
        scanf("%s%d",stu.name,&stu.score);
        switch(stu.score/10)
        {
        case 10:
        case 9:
            stu.rank='A';break;
        case 8:
            stu.rank='B';break;
        case 7:
            stu.rank='C';break;
        case 6:
            stu.rank='D';break;
        default:
            stu.rank='E';break;
        }
        fwrite(&stu,sizeof(struct student),1,fp);
        scanf("%d",&stu.num);
    }
    fclose(fp);

    fp=fopen(FILENAME,"rb");
    if(fp==NULL)
    {
        printf("不能打开文件：%s
",FILENAME);
        exit(1);
    }
    printf("学号 姓名 成绩 等级
");
    fread(&stu,sizeof(struct student),1,fp);
    while(!feof(fp))
    {
        printf("%d %s  %d  %c
",stu.num,stu.name,stu.score,stu.rank);
        fread(&stu,sizeof(struct student),1,fp);
    }
    fclose(fp);

    return 0;
}