C语言-文件块操作

 1 #include <stdio.h>
 2 #include <stdlib.h>
 3 #define FILENAME "E:\\FUSHI\\students.txt"
 4 
 5 struct student
 6 {
 7     int num;//学号
 8     char name[20];//姓名
 9     char rank; //成绩等级
10     int score;//成绩
11 };
12 
13 int main()
14 {
15     FILE *fp;
16     struct student stu;
17     fp=fopen(FILENAME,"wb");
18     if(fp==NULL)
19     {
20         printf("不能打开文件：%s\n",FILENAME);
21         exit(1);
22     }
23     printf("请输入学生的学号、姓名、成绩：\n");
24     scanf("%d",&stu.num);
25     while(stu.num!=0)
26     {
27         scanf("%s%d",stu.name,&stu.score);
28         switch(stu.score/10)
29         {
30         case 10:
31         case 9:
32             stu.rank='A';break;
33         case 8:
34             stu.rank='B';break;
35         case 7:
36             stu.rank='C';break;
37         case 6:
38             stu.rank='D';break;
39         default:
40             stu.rank='E';break;
41         }
42         fwrite(&stu,sizeof(struct student),1,fp);
43         scanf("%d",&stu.num);
44     }
45     fclose(fp);
46 
47     fp=fopen(FILENAME,"rb");
48     if(fp==NULL)
49     {
50         printf("不能打开文件：%s\n",FILENAME);
51         exit(1);
52     }
53     printf("学号 姓名 成绩 等级\n");
54     fread(&stu,sizeof(struct student),1,fp);
55     while(!feof(fp))
56     {
57         printf("%d %s  %d  %c\n",stu.num,stu.name,stu.score,stu.rank);
58         fread(&stu,sizeof(struct student),1,fp);
59     }
60     fclose(fp);
61 
62     return 0;
63 }