閱讀下列說明和C++代碼，填補(bǔ)代碼中的空缺，將解答填入答題紙的對應(yīng)欄內(nèi)。
【說明】
以下C++代碼實(shí)現(xiàn)一個簡單客戶關(guān)系管理系統(tǒng)（CrM）中通過工廠（Customerfactory）對象來創(chuàng)建客戶（Customer）對象的功能?？蛻舴譃閯?chuàng)建成功的客戶（realCustomer）和空客戶（NullCustomer）?？湛蛻魧ο笫钱?dāng)不滿足特定條件時(shí)創(chuàng)建或獲取的對象。類間關(guān)系如圖6-1所示。

【C++代碼】
#include
#include
using namespace std;
 
class Customer｛
protected:
     string name;
public:
   （   1   ） boll isNil()=0;
   （   2   ） string getName()=0;
﹜;
 
class RealCustomer (   3   )｛
Public:
     realCustomer(string name)｛this->name=name;﹜
     bool isNil()｛ return false;  ﹜  
     string getName()｛ return name;  ﹜
﹜;
class NullCustomer (    4   ) ｛
public:
     bool isNil()｛  return true; ﹜
     string getName()｛ return 〝Not Available in Customer Database〞; ﹜
﹜;
 
class Customerfactory｛
public:
    string names［3］=｛〝rob〞, 〝Joe〞,〝Julie〞﹜;
public:
Customer*getCustomer(string name)｛
   for （int i=0;i<3;i++)｛
       if （names[i].(   5   ) )｛
           return new realCustomer(name);
      ﹜
    ﹜
     return (   6   );
  ﹜
﹜;
 
class CRM｛
public:
    void getCustomer()｛
         Customerfactory*(   7   );
         Customer*customer1=cf->getCustomer(〝Rob〞);
Customer*customer2=cf->getCustomer(〝Bob〞);
Customer*customer3=cf->getCustomer(〝Julie〞);
Customer*customer4=cf->getCustomer(〝Laura〞);
 
cout<<〝Customers〞<<endl;
 cout<getName()<<endl;  delete customer1;
 cout<getName()<<endl;  delete customer2;
 cout<getName()<<endl;  delete customer3;
 cout<getName()<<endl;  delete customer4;
 delete cf;
         ﹜
     ﹜;
 int main()｛
      CRM*crs=new CRM();
      crs->getCustomer();
      delete crs;
      return 0;
﹜
 
/*程序輸出為：
Customers
rob
Not Available in Customer Database
Julie
Not Available in Customer Database
*/</endl;  delete customer4;
</endl;  delete customer3;
</endl;  delete customer2;
</endl;  delete customer1;
</endl;