Anne的宠物小屋有12个笼子，每个笼子可以放不同的动物，但只能放1只或0只，包括猫Cat，狗Dog，蛇Snake.

　　1，实现一个简单的管理系统，可增加、删除笼子中的宠物，查询每个笼子中存放的宠物类型，（包括笼子为空的情况），统计笼中宠物的种类和数量。

　　2，定义描述宠物小屋的类shelves，其中有12笼子用于存放各种宠物。

　　3，定义虚拟基类Animal，包括纯虚函数ShowMe，显示每个宠物的情况，包括类型、颜色、体重和喜爱的食物。

　　4，定义派生类Cat，Dog，Snake，具体实现上述纯虚函数。

　　5，重载输入‘>>’*作符，使得可能通过cin直接读入宠物颜色、体重和喜爱的食物。

　　6，编写main函数，测试上述要求和各种功能。

    */ 
#include "Stdafx.h"
#include "iostream.h"
#include "string.h"
enum {NONE=0, CAT=1, DOG=2, SNAKE=3};
class Animal
{
protected:
 char color[20];
 char food[20];
 double weight;
public:
 virtual void ShowMe()=0;
};
class Cat:public Animal
{
public:
 friend istream& operator>>(istream &is, Cat &cat);
 void ShowMe()
 {
  cout<<"猫的颜色、喜欢的食物、体重分别为:";
  cout<<color<<","<<food<<","<<weight<<endl;  
 }
};
istream & operator>>(istream &is, Cat &cat)
{
 cout<<" 请输入猫的颜色: "; 
 is>>cat.color; 
 cout<<" 喜爱的食物:";
 is>>cat.food; 
 cout<<" 体重:";
 is>>cat.weight; 
 return is;
}

class Dog:public Animal
{
public:
 friend istream& operator>>(istream &is, Dog &Dog);
 void ShowMe()
 {
  cout<<"狗的颜色、喜欢的食物、体重分别为:";
  cout<<color<<","<<food<<","<<weight<<endl;  
 }
};
istream& operator>>(istream &is, Dog &dog)
{
 cout<<" 请输入狗的颜色: "; 
 is>>dog.color;
 cout<<" 喜爱的食物:";
 is>>dog.food;
 cout<<" 体重:";
 is>>dog.weight; 
 return is;
}
class Snake:public Animal
{
public:
 friend istream& operator>>(istream &is, Snake &snake);
 void ShowMe()
 {
  cout<<"蛇的颜色、喜爱的食物、体重分别为：";
  cout<<color<<","<<food<<","<<weight<<endl;  
 }
};
istream& operator>>(istream &is, Snake &snake)
{
 cout<<" 请输入蛇的颜色: "; 
 is>>snake.color;
 cout<<" 喜爱的食物: ";
 is>>snake.food;
 cout<<" 体重: ";
 is>>snake.weight;
 return is;
}
class Shelves
{
 int cage[12];
 int sum[3];
 Cat cats[12];
 Dog dogs[12];
 Snake snakes[12];
// int flag[12];
// int sum_c, sum_d, sum_s;
public:
 Shelves ()
 {
  for (int i=0; i<12; i++)
   cage[i]=NONE;
  for (i=0; i<4; i++)
   sum[i]=0;
 }
 int push_cat(Cat &cat, int n)
 {
  cats[n] = cat;  
  if (cage[n]!=NONE) return 0;
  else {
   sum[0]++;
   return cage[n]=CAT;
  }
 }
 int push_dog(Dog &dog, int n)
 {
  dogs[n]=dog;  
  if (cage[n]!=NONE) return 0;
  else{
   sum[1]++;
   return cage[n]=DOG;
  }
 }
 int push_snake(Snake &snake, int n)
 {  
  snakes[n]=snake;  
  if (cage[n]!=NONE) return 0;
  else {
   sum[2]++;
   return cage[n]=SNAKE;
  }
 }
 void del(int n)
 {
  if (cage[n]==CAT) sum[0]--;
  if (cage[n]==DOG) sum[1]--;
  if (cage[n]==SNAKE) sum[2]--;
  if (cage[n]==NONE)
   cout<<"笼子里没有动物"<<endl;
  else
  { 
   cage[n]=NONE;
   cout<<"已删除笼子里的动物"<<endl;
  }  
  cout<<endl;
 }
 void seek(int n)
 {
  if (cage[n]==NONE) cout<<"第"<<n<<"个笼子里没有动物"<<endl;
  if (cage[n]==CAT)
  {
   cout<<"第"<<n<<"个笼子里的动物为猫,";
   cats[n].ShowMe();
  }
  if (cage[n]==DOG)
  {
   cout<<"第"<<n<<"个笼子里的动物为狗,";
   dogs[n].ShowMe();
  }
  if (cage[n]==SNAKE)
  {
   cout<<"第"<<n<<"个笼子里的动物为蛇,";   
   snakes[n].ShowMe();
  }
  cout<<endl;  
 }
 void count()
 {  
  cout<<"笼子里的猫总共有："<<sum[0]<<"只"<<endl;
  cout<<"笼子里的狗总共有："<<sum[1]<<"只"<<endl;
  cout<<"笼子里的蛇总共有："<<sum[2]<<"只"<<endl;
  cout<<endl;
 }
};
void main()
{
 char c;
 Cat cat;
 Dog dog;
 Snake snake;
 Shelves shelves;
 int i=1,j;
 cout<<"这是关于往笼子里放动物的问题: "<<endl;
 cout<<endl;
  cout<<" 1: 往笼子里放猫；"<<endl;
  cout<<" 2: 往笼子里放狗；"<<endl;
  cout<<" 3: 往笼子里放蛇；"<<endl;
  cout<<" 4: 查询笼子里的动物；"<<endl;
  cout<<" 5: 删除笼子里的动物；"<<endl;
  cout<<" 6：统计笼子里的动物种类及数量；"<<endl;
  cout<<" 7: 退出程序;"<<endl;
  cout<<"------------------------------------------"<<endl;
 while(i)
 {
  cout<<"请选择您的*作：";
  cin>>i;
  switch(i)
  {
  case 1:
   cout<<" 往哪只笼子里面放: ";
   cin>>j;
   cin>>cat;    
   while (shelves.push_cat(cat, j)==0)
   {
    cout<<" 笼子里已有动物，请换一个笼子: ";
    cin>>j;
   }
   break;
  case 2:
   cout<<" 往哪只笼子里面放: ";
   cin>>j;
   cin>>dog;    
   while (shelves.push_dog(dog, j)==0)
   {
    cout<<" 笼子里已有动物，请换一个笼子: ";
    cin>>j;
   }
   break;
  case 3:
   cout<<" 往哪只笼子里面放: ";
   cin>>j;
   cin>>snake;    
   while (shelves.push_snake(snake, j)==0)
   {
    cout<<" 笼子里已有动物，请换一个笼子: ";
    cin>>j;
   }
   break;
  case 4: 
   cout<<" 查询哪只笼子: ";
   cin>>j;
   shelves.seek(j);
   break;
  case 5: 
   cout<<" 删除哪只笼子里的动物: ";
   cin>>j;
   shelves.del(j); break;
  case 6:
   shelves.count(); break;
  default: i=0; break;
  }
  cout<<endl;
 }
}