#include?
#include?
#include?

struct?Student
{
????int?id;
????char?name[20];
????int?age;
????struct?Student?*next;
};

enum?my_func
{
????f_add=1
????f_delate
????f_find
????f_change
????f_printf_all
????ESC
};

void?add（struct?Student?*p_head）;
void?delate（struct?Student?*p_head）;
void?find（struct?Student?*p_head）;
void?change（struct?Student?*p_head）;
void?printf_all（struct?Student?*p_head）;
void?menu（struct?Student?*p_head）;
int?num?=?0;

int?main（）
{
????struct?Student?*p_head?=?（struct?Student?*）malloc（sizeof（struct?Student））;
????p_head->next?=?NULL;

????menu（p_head）;

????return?0;
}


void?menu（struct?Student?*p_head）
{???
????int?choose=0;
????while?（1）
????{
????????printf（“****************************\n“）;
????????printf（“***?歡迎使用學生管理系統???***\n“）;
????????printf（“***???1、增加學生信息?????***\n“）;
????????printf（“***???2、刪除信息?????????***\n“）;
????????printf（“***???3、查詢信息?????????***\n“）;
????????printf（“***???4、更改信息?????????***\n“）;
????????printf（“***???5、打印所有學生信息??***\n“）;
????????printf（“***???6、退出?????????????***\n“）;
????????printf（“***?學生總人數：%d?????????***\n“?num）;
????????printf（“*****************************\n“）;
????????printf（“***??請輸入你的選項序號??***\n“）;
????????scanf（“?%d“?&choose）;
????????getchar（）;??//等待輸入ENTER
????????printf（“***************************\n“）;

????????switch?（choose）
????????{
????????????case?f_add:
????????????????add（p_head）;
????????????????break;
????????????case?f_delate:
????????????????delate（p_head）;
????????????????break;
????????????case?f_find:
????????????????find（p_head）;
????????????????break;
????????????case?f_change:
????????????????change（p_head）;
????????????????break;
????????????case?f_printf_all:
????????????????printf_all（p_head）;
????????????????break;
????????????case?ESC:
????????????????printf（“成功退出，歡迎再次使用!\n“）;
????????????????return;
????????????default:
????????????????printf（“輸入有誤，請重新輸入!\n“）;
????????}
????}
???
}

void?add（struct?Student?*p_head）
{
????struct?Student?*p?=?p_head;
????struct?Student?*tmp?=?（struct?Student?*）malloc（sizeof（struct?Student））;
????tmp->next?=?NULL;
????printf（“請輸入你要添加學生的ID\n“）;
????scanf（“%d“?&tmp->id）;
????getchar（）;
????
????while?（1）
????{
????????if（p->next?==?NULL）?????????//剛開始?p->next?=?NULL;
????????{
????????????p->next?=?tmp;
????????????tmp->next?=?NULL;
????????????p->next->id?=?tmp->id;
????????????num++;
????????????tmp?=?NULL;
????????????break;
????????}
????????if（p->next->id?==?tmp->id）
????????{
????????????printf（“ID重復，請重新輸入\n“）;
????????????scanf（“%d“?&tmp->id）;
????????????getchar（）;
????????????p?=?p_head;
????????}else
????????{
????????????p?=?p->next;????//移動
????????}
????}

????printf（“請輸入你要添加學生的姓名\n“）;
????scanf（“%s“?p->next->name）;
????getchar（）;
????printf（“請輸入你要添加學生的年齡\n“）;
????scanf（“%d“?&p->next->age）;
????getchar（）;

????printf（“你添加的學生的信息是：\n“）;
????pri