#include<stdio.h>
#include<stdlib.h>
#include<string.h>
#define NUM 5

struct item{
 char brand[20];
 char id[10];
 float in_price;
 float out_price;
 int storage;
};
struct item_node{
 struct item wanted;
 int amount;
 struct item_node *next;
};

int menu();
void establish();
void dis_all();
void shop_cart();
int cart_menu();
void add();
void display();
void calculate();

struct item goods[NUM];
struct item_node *cart;


void main()
{
 printf("***********************************\n");
 printf("  歡迎進(jìn)入超市管理系統(tǒng)\n");
 printf("***********************************\n");
 while(1)
 {
 switch(menu())
 {
 case 1:
 establish();break;
 case 2:
 dis_all();break;
 case 3:
 shop_cart();break;
 case 4:
 calculate();break;
 case 5:
 printf("感謝使用，再見!\n");
 exit(0);
 }
 }
}

int menu()
{
 char str[5];
 int select;
 printf("\n\n請(qǐng)選擇數(shù)字進(jìn)行操作\n");
 printf("1.建立庫存信息\n");
 printf("2.顯示所有信息\n");
 printf("3.購物車\n");
 printf("4.結(jié)算\n");
 printf("5.退出\n");
 printf("請(qǐng)選擇對(duì)應(yīng)數(shù)字1--5");
 while(1)
 {
 fflush(stdin);
 gets(str);
 select=atoi(str);
 if(select<1||select>5)
 printf("輸入錯(cuò)誤，請(qǐng)重新輸入:");
 else
 break;
 
 }
 return select;
 
}

void dis_all()
{
 int i;
 FILE *fp;
 fp=fopen("goods","r");
 for(i=0;(fread(goods+i,sizeof(struct item),1,fp))!=0;i++)
 {
 printf("---------------------------------\n");
 printf("貨品 品名 單價(jià)  庫存量\n");
 printf("%s%7s%7.2f%8d\n",goods[i].id,goods[i].brand,goods[i].out_price,goods[i].storage);
 
 }
 fclose(fp);
}


void shop_cart()
{
 while(1)
 {
 switch(cart_menu())
 {
 case 1:
 display();break;
 case 2:
 add();break;
 case 3:
 return;
 }
 }
}
int cart_menu()
{
 char str[5];
 int select;
 printf("\n請(qǐng)選擇操作\n");
 printf("-----------------------\n");
 printf("1.顯示當(dāng)前購物列表\n");
 printf("2.添加商品\n");
 printf("3.退出\n");
 printf("-----------------------\n\n");
 while(1)
 {
 fflush(stdin);
 gets(str);
 select=atoi(str);
 if(select<1||select>3)
 printf("輸入錯(cuò)誤，請(qǐng)重新輸入:");
 else
 break;
 }
 return select;
}

void display()
{
 struct item_node *p=cart;
 if(p==NULL){
 printf("購物車為空\n");
 return ;
 }
 while(p!=NULL){
 printf("----------------------------------\n");
 printf("貨號(hào)    品名 單價(jià) 數(shù)量\n");
 printf("%10s%20s%7.2f%8d\n",p->wanted.id,p->wanted.brand,p->wanted.out_price,p->amount);
 p=p->next;
 }
}

void add()
{
 FILE *fp;
 int i,n;
 char str[20];
 char choice1,choice2;
 struct item_node *p,*p1;
 do
 {
 printf("輸入所需物品的名稱或貨號(hào): ");
 fflush(stdin);
 gets(str);
 if((fp=fopen("goods","r"))==NULL){
 printf("打開文件失敗\n");
 continue;
 }
 for(i=0;fread(goods+i,sizeof(struct item),1,fp)!=0;i++){
 if((strcmp(goods[i].brand,str)==0||strcmp(goods[i].id,str)==0)&&goods[i].storage!=0){
 printf("已經(jīng)找到所需物品: \n");
 printf("---------------------\n");
 printf("貨號(hào) 品名 單價(jià) 庫存量\n");
 printf("%s%6s%3.2f%4d\n",goods[i].id,goods[i].brand,goods[i].out_price,goods[i].storage);
 printf("請(qǐng)輸入所需數(shù)量: ");
 scanf("%d",&n);
 if(n>goods[i].storage){
  printf("庫存不足\n");
  break;
 }
 printf("\n是否購買?(Y/N)");
 fflush(stdin);
 choice1=getchar();
 if(choice1=='Y'||choice1=='y'){
  p1=(struct item_node*)malloc(sizeof(struct item_node));
  if(p1==NULL){
  printf("內(nèi)存申請(qǐng)失敗!\n");
  exit(1);
  }
  p1->amount=n;
  p1->wanted=goods[i];
  p1->next=NULL;
  p=cart;
  if(cart==NULL)
  cart=p1;
  else{
  while(p->next!=NULL)
  p=p->next;
  p1->next=p->next;
  p->next=p1;
  }
 }
 break;
 }
 }
 if(i==NUM)
 printf("未找到所需物品\n");
 fclose(fp);
 printf("是否繼續(xù)購物?(Y/N)");
 fflush(stdin);
 choice2=getchar();
 }while(choice2=='Y'||choice2=='y');
}


void establish(){
 FILE *fp;
 int i;
 printf("請(qǐng)依次輸入貨物信息:\n");
 printf("----------------------------\n");
 for(i=0;i<NUM;i++)
 {
 printf("品名: ");
 fflush(stdin);
 gets(goods[i].brand);
 printf("貨號(hào): ");
 fflush(stdin);
 gets(goods[i].id);
 printf("進(jìn)價(jià): ");
 fflush(stdin);
 scanf("%f",&goods[i].in_price);
 printf("哨價(jià): ");
 fflush(stdin);
 scanf("%f",&goods[i].out_price);
 printf("數(shù)量: ");
 fflush(stdin);
 scanf("%d",&goods[i].storage);
 printf("\n");
 }
 if((fp=fopen("goods","w"))==NULL){
 printf("創(chuàng)建文件失敗.\n");
 return;
 }
 fwrite(goods,sizeof(struct item),NUM,fp);
 fclose(fp);
}

void calculate()
{
 float total=0,pay;
 struct item_node *p;
 int i;
 FILE *fp;
 printf("以下是購物清單: \n");
 display();
 if((fp=fopen("goods","r"))==NULL){
 printf("打開文件失敗: \n");
 return;
 }
 for(i=0;(fread(goods+i,sizeof(struct item),1,fp))!=0;i++);
 fclose(fp);
 p=cart;
 while(p!=NULL){
 total+=p->wanted.out_price*p->amount;
 for(i=0;strcmp(goods[i].id,p->wanted.id)!=0;i++);
 goods[i].storage-=p->amount;
 p=p->next;
 }
 printf("總計(jì) %7.2f",total);
 printf("\n輸入實(shí)付金額: ");
 scanf("%f",&pay);
 printf("實(shí)付:   %7.2f 找零:   %7.2f",pay,pay-total);
 if((fp=fopen("goods","w"))==NULL){
 printf("打開文件失敗.\n");
 return;
 }
 fwrite(goods,sizeof(struct item),NUM,fp);
 fclose(fp);
}