代码：

 1 //This is c program code!
 2 /* *=+=+=+=+* *** *=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=
 3   * 文档信息: *** :~/WORKM/stutyCode/cCode/recipesProblemSolution/chapter06/test6_12.c
 4   * 版权声明: *** :(魎魍魅魑)MIT
 5   * 联络信箱: *** :guochaoxxl@163.com
 6   * 创建时间: *** :2020年11月21日的下午04:25
 7   * 文档用途: *** :数据结构与算法分析-c语言描述
 8   * 作者信息: *** :guochaoxxl(http://cnblogs.com/guochaoxxl)
 9   * 修订时间: *** *2020年第46周 11月21日 星期六 下午05:03 (326天)
10   * 文件描述: *** :自行添加
11  * *+=+=+=+=* *** *+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+=+*/
12 #include <stdio.h>
13 
14 typedef struct _bio{
15     char name[15];
16     int rollNo;
17     int age;
18     float weight;
19 } Bio;
20     
21 void closeState(int clo, FILE *fPtr){
22     clo = fclose(fPtr);
23     if(clo == -1){
24         puts("File-closing failed!");
25     }
26     if(clo == 0){
27         puts("File is closed successfully.");
28     }
29 
30     return;
31 }   
32     
33 int main(int argc, char **argv)
34 {   
35     char flag = 'y';
36     FILE *fPtr = fopen("agentsb.dat", "wb");
37     if(fPtr != NULL){
38         printf("File agentsb.dat is opened successfully.\n");
39         Bio bio;
40         while(flag == 'y'){
41             printf("Enter name, rooNo, age and weight of agent: ");
42             scanf("%s %d %d %f", bio.name, &bio.rollNo, &bio.age, &bio.weight);
43             fwrite(&bio, sizeof(bio), 1, fPtr);
44             int tmp = getchar();
45             //fflush(stdin);
46             printf("Any more records(y/n): ");
47             scanf("%c", &flag);
48         }
49         int clo = fclose(fPtr);
50         closeState(clo, fPtr);
51     }else{
52         puts("File-open failed!");
53     }
54 
55     return 0;
56 }