小明的宠物小屋有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，兔Rabbit。

（1）实现一个简单的宠物管理系统，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、体重和喜爱的食物等；

（4）定义派生类Cat、Dog、Snake，具体实现上述纯虚函数；

（5）重载输入操作符“>>”，使得可以通过cin命令直接读入宠物颜色、体重和喜爱的食物。

-Xiao Ming s pet lodge has 12 cages, each cage can put different animals, but only put one or 0, including cats Cat, Dog Dog, Rabbit Rabbit.

(1) to achieve a simple pet management system and add, delete cage pet query stored in each cage pet types (including cage is empty), the statistical pet cage types and quantities

(2) The definition describes a class pet lodge Shelves, of which 12 for storing all kinds of pet cages

(3) define a virtual base class Animal, including a pure virtual function ShowMe, display of each pet, including the type, color, weight and favorite foods and the like

(4) definition of the derived class Cat, Dog, Snake, concrete realization of the above-mentioned pure virtual function

(5) overloaded input operator　>>　makes it possible to read directly　the cin command Pets color, weight and favorite food.