#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#define Insert 1 //增加订单
#define Query  2 //查找订单
#define Update 3 //修改订单
#define Delete 4 //删除订单
#define List   5 //列出所有订单
#define Quit   0 //退出系统
FILE *fp;
struct Node
{
    char name[20];
    char foodname[20];
    int sum;
    char time[20];
    int number;
    struct Node *next;
};
struct Node *pointer,*tail;   //pointer指向第一订餐的学生，tail指向最近一次订餐的学生
int last=0; //当前订餐总人数
void showMenu();
void doChoice(int);
int  getChoice();
void doQuit();
void doInsert();
void doUpdate();
void doQuery();
void doDelete();
void doListAll();
void init();
int main(int argc,char *argv[])
{
    int choice;    //用户选择功能
    init();        //从文件中初始化订餐信息
    while(1)
    {
       showMenu();             //显示主菜单
       choice=getChoice();     //获取用户选择
       doChoice(choice);
       system("pause>nul") ;      //执行用户选择
    }
    return 0;
}
void init()
{
    int i=0;
    struct Node *p;
    pointer=tail=NULL;   
    if((fp=fopen("order.dat","rb"))==NULL)
    {
        last=0;//当前没有订餐数据
    }
    else
    {
        while(!feof(fp))
        {
            if((p=(struct Node *)malloc(sizeof(struct Node)))==NULL)
            {
                printf("系统内存故障，退出程序");
                exit(0);
            }
            if(fread(p,sizeof(struct Node),1,fp)==1)
            {
                if(i==0)
                {
                   pointer=tail=p;   //第一个订餐学生
                    
                }
                i++;
                tail->next=p;
                tail=p;
            }
        }
        tail->next=NULL;
        last=i;
    }
    fclose(fp);
}
void save()   //保存订单信息到文件pointer.txt中
{
    struct Node *p=pointer;
    if((fp=fopen("order.txt","wb"))==NULL)
    {
        printf("不能打开订单信息，请检查");
        exit(0);
    }
    while(p!=NULL)
    {
        if(fwrite(p,sizeof(struct Node),1,fp)==1)
        {
            p=p->next;
        }
    }
    fclose(fp);
}
void showMenu()
{
    system("cls");
    printf("**********Student Food-Order System*********\n");
    printf("\t\t1.   点外卖\n");
    printf("\t\t2.   查找订单\n");
    printf("\t\t3.   修改订单\n");
    printf("\t\t4.   删除订单\n");
    printf("\t\t5.   查看所有订单\n");
    printf("\t\t6.   退出系统\n");
    printf("************************\n");
    printf("请输入你的选择(0---6):\n");
}
void doQuit()
{
    printf("\n欢迎使用本系统，再见!");
    exit(0);
}
void doInsert()
{
    struct Node *p;
    if((p=(struct Node *)malloc(sizeof(struct Node)))==NULL)
    {
        printf("该店点餐人员爆满，请稍后进入");
        return ;
    }
    printf("请输入编号:");
    scanf("%d",&(p->number));
    printf("请输入姓名:");
    scanf("%s",p->name);
    printf("请输入菜名:");
    scanf("%s",p->foodname);
    printf("请输入人数:");
    scanf("%d",&(p->sum));
    printf("请输入用餐时间:");
    scanf("%s",p->time);
    printf("点餐成功\n");
    if(tail!=NULL)
    {
        tail->next=p;
        tail=tail->next;
    }
    else
    {
        {
       for(p=pointer;p->next!=NULL;p=p->next)
       p->next=p;
        }
        tail->next=NULL;
        last++;
        save();
    }

}
void doUpdate()
{
    int number;
    int i;
    int find=0;
    struct Node *p=pointer;
    printf("请输入要修改的订单号码:");
    scanf("%d",&number);
     while((p!=NULL)&&(!find))
   { if(p->number==number)
      {
        find=1;
        printf("你要找的订单信息如下:\n");
        printf("*******************************");
        printf("姓名:%s\t",p->name);
        printf("菜名:%s\t",p->foodname);
        printf("人数:%d\t",p->sum);
        printf("用餐时间%s\t",p->time);
        printf("*******************************");
        printf("请输入修改后的信息:\n");
        printf("姓名:\n");
        scanf("%s",p->name);
        printf("菜名:\n");
        scanf("%s",p->foodname);
        printf("人数:\n");
        scanf("%d",&(p->sum));
        printf("请输入用餐时间:\n");
        scanf("%s",p->time);
      }
    p=p->next;
   }
   if(!find)
       {
        printf("无法找到该订单，请重新下单\n");
       }
       else
       {
        printf("该订单修改成功\n");
        save();
       }
       p=NULL;
}
void doListAll()
{
    struct Node *p=pointer;
    printf("该店目前有%d人在线\n",last);
    while(p!=NULL)
    {
        printf("*******************************\n");
        printf("姓名:%s\t",p->name);
        printf("菜名:%s\t",p->foodname);
        printf("人数:%d\t",p->sum);
        printf("用餐时间%s\n",p->time);
        p=p->next;
    }
    printf("***************************\n");
}
void doQuery()
{
    int number;
    int i;
    int find=0;
    struct Node *p=pointer;
    printf("处理查询.....\n");
     printf("请输入订单号码:");
    scanf("%d",&number);
     while((p!=NULL)&&(!find))
   { if(p->number==number)
      {
        find=1;
        printf("你要找的订单信息如下:\n");
        printf("*******************************\n");
        printf("姓名:%s\t",p->name);
        printf("菜名:%s\t",p->foodname);
        printf("人数:%d\t",p->sum);
        printf("用餐时间%s\t",p->time);
      }
      p=p->next;
   }
   if(!find)
   {
    printf("没有此订单\n");
   }
}
void doDelete()
{
    int number;
    int i;
    int find=0;
    int index;
    struct Node *p=pointer;
    struct Node *pre=pointer;
    printf("处理删除.....\n");
    printf("请输入订单编号:\n");
    scanf("%d",&number);
     while((p!=NULL)&&(!find))
   {
     if(p->number==number)
     {
        find=1;
        index=i;
        break;
     }
     pre=p;
     p=p->next;
   }
   if(!find)
   {
    printf("没有该编号订单\n");
   }
   else
   {
    if(p==pre)
    {
        pointer=NULL;
        last=0;
    }
    else
    {
        pre->next=p->next;
        last--;
        printf("订单已删除\n");
        save();
    }
   }
}
int getChoice()
{
    int choice;
    scanf("%d",&choice);
    return choice;
}
void doChoice(int choice)
{
    switch(choice)
    {
        case Insert:
        doInsert();
        break;
        case Query:
        doQuery();
        break;
        case Update:
        doUpdate();
        break;
        case Delete:
        doDelete();
        break;
        case List:
        doListAll();
        break;
        case Quit:
        doQuit();
    }
}