C语言实现的图书管理系统基础操作

#include<stdio.h>
#include "stdlib.h"
#include "conio.h"
#include "string.h"
#include "math.h"
#define LEN sizeof(struct library)
#define LEN1 sizeof(struct reader)
#define NULL 0
struct library//图书馆结构体
{int shuhao,xcl;
char name[20],author[20],chuban[20];
struct library *next;
};

struct reader//读者结构体
{
int zhenghao;
char mingzi[20],riqi[20],zname[20];
struct reader *next;
};

void mainmenu()  //显示主菜单
{ system ("cls");
 printf("********************************************************************************");
    printf("*^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^*");
 printf("\t\t\t\t  1.图书馆信息\n\n");
 printf("\t\t\t\t  2.借阅系统\n\n");
 printf("\t\t\t\t  3.退出系统\n\n");
 printf("\t\t\t       请按键选择，回车确定\n");
 printf("*^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^*");

 printf("********************************************************************************");
 return ;
}

void menu1()  //显示图书馆信息菜单
{ system ("cls");
 printf("********************************************************************************");
    printf("*^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^*");
 printf("\t\t\t\t  1.采编入库\n\n");
 printf("\t\t\t\t  2.清除库存\n\n");
 printf("\t\t\t\t  3.图书查询\n\n");
 printf("\t\t\t\t  4.库存一览\n\n");
 printf("\t\t\t\t  5.返回上一层\n\n");
 printf("\t\t\t       请按键选择，回车确定\n");
 printf("*^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^*");
 printf("********************************************************************************");
 return ;
}
void menu2()  //显示查询菜单
{ system ("cls");
 printf("********************************************************************************");
    printf("*^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^*");
 printf("\t\t\t\t  1.书号查询\n\n");
 printf("\t\t\t\t  2.书名查询\n\n");
 printf("\t\t\t\t  3.作者查询\n\n");
 printf("\t\t\t\t  4.出版社查询\n\n");
 printf("\t\t\t       请按键选择，回车确定\n");
 printf("*^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^  ^_^*");
 printf("********************************************************************************");
 return ;