程序代码：

#include<stdio.h>
#include<stdlib.h>
#include<string.h>

typedef struct bk {
char book_num[10];
char book_name[10];
int book_kc;
int book_xc;
struct bk * next;
}book;

struct bk *l;
void save();
void menu();
void  putin();
void search() ;
void lend();
void reback();
void save(char book_num[],char book_name[],int num)
{   FILE *book_fp;
   struct bk *t;
  if((book_fp=fopen("e:book.txt","a+"))==NULL)
{  printf("不能建立图书文件!\n"); return; }
   t=(struct bk *)malloc(sizeof(struct bk));
   strcpy(t->book_num,book_num);
   strcpy(t->book_name, book_name);
   t->book_kc=t->book_xc=num;
   l->next=t;t->next=NULL;
   fwrite(t,sizeof(struct bk),1,book_fp);
   free(t);
   fclose(book_fp);
}
void  putin()
{
   struct bk *p;
   p=(struct bk *)malloc(sizeof(struct bk));
   int number;
   int  y=1;
   system("cls");
   while(y)
   {
  printf("请输入您的书的编号：");
  scanf("%s",p->book_num);
  printf("请输入书名:");
  scanf("%s",p->book_name);
  printf("请输入您要存的数量：");
  scanf("%d",&number);
  save(p->book_num,p->book_name,number);
  printf("\n是否继续录入(1.继续;0,退出录入):");

 
  scanf("%d",&y);
  switch(y)
{
     case 1:putin();
     break;
     case 0:system("cls");menu();
     break;
   
}
}
    
}
void search()
{  struct bk *p; 
   p=(struct bk *)malloc(sizeof(struct bk));
   printf("请输入您的书的编号：");
   scanf("%s",p->book_num);
   while(p!=NULL&&strcmp(p->book_num,l->book_num)!=0)
  { l=l->next;
   if(l==NULL) printf("\n\t此编号对应的图书不存在!\n");
  }
       printf("\n\t图书编号\t图书名\t库存量\t现存量 \n");
    printf(" %10s\t %10s\t %d\t %d\t\n",l->book_num,l->book_name,l->book_kc,l->book_xc);
    menu();
  

}
void lend()
{ struct bk *q; 
  q=(struct bk *)malloc(sizeof(struct bk));
  printf("请输入您的书的编号：");
  scanf("%s",q->book_num);
  while(q!=NULL&&strcmp(q->book_num,l->book_num)!=0)
{
     l=l->next;
  if(l==NULL)
  printf("\n\t此编号对应的图书不存在！\n");
}
  printf("\n\t图书编号\t图书名\t库存量\t现存量 \n");
printf(" %10s\t %10s\t %d\t %d\t\n",l->book_num,l->book_name,l->book_kc,l->book_xc); 

l->book_xc=l->book_xc-1;
save(l->book_num,l->book_name,l->book_xc);
menu();
} 

void reback()
{
   struct bk *b; 
   b=(struct bk *)malloc(sizeof(struct bk));
   printf("请输入您的书的编号：");
   scanf("%s",b->book_num);
   while(b!=NULL&&strcmp(b->book_num,l->book_num)!=0)
  {
      l=l->next;
   if(l==NULL)
   printf("\n\t此编号对应的图书不存在！\n");
  }
     l->book_xc=l->book_xc+1;
    save(b->book_num,b->book_name,b->book_xc);
    printf("\n\t图书编号\t图书名\t库存量\t现存量 \n");
    printf(" %10s\t %10s\t %d\t %d\t\n",l->book_num,l->book_name,l->book_kc,l->book_xc);
       printf("\n您的书几经归还,谢谢!") ;
       menu();
} 
void display()
{
    FILE *fq;
    struct bk _t;
    fq=fopen("e:book.txt","rb");
    while((fread(&_t,sizeof(struct bk),1,fq))==1)
    {printf(" %10s\t %10s\t %d\t %d\t\n",_t.book_num,_t.book_name,_t.book_kc,_t.book_xc);}
    fclose(fq);
}
void menu()
{ void diaplay();
int lm;
printf(" \n               *****************************************************                    ");
printf(" \n                                    ★图书管理系统★                                 ");
printf(" \n                                       ㈠图书入库                                   ");
printf (" \n                                     ㈡查询图书                                 ");
printf(" \n                                      ㈢图书借阅                                  ");
printf(" \n                                    ㈣图书归还                                    ");
printf(" \n                                     ㈤退出系统                                     ");
printf(" \n                           按上述1/2/3/4/5数字键选择以上功能                    ");
printf(" \n             *******************************************************                       ");    

scanf("%d",&lm);  
switch(lm)
{
    case 1:putin();
    break;
    case 2:search();
    break;
    case 3:lend();
    break;
    case 4:reback();
    case 5:break;
    case 6:display();
}
}

main()
{
    l=(struct bk *)malloc(sizeof(struct bk));
    menu();
    return 0;
}