錯誤C2248：'std :: basic_ios <_Elem，_Traits> :: basic_ios'：無法訪問在類中聲明的私有成員'std :: basic_ios <_Elem，_Traits>'

Question

我無法理解此錯誤。不在我正在調試的類中。 （是嗎？） 的錯誤是：

c:\program files\microsoft visual studio 10.0\vc\include\fstream(890): error C2248: 'std::basic_ios<_Elem,_Traits>::basic_ios' : cannot access private member declared in class 'std::basic_ios<_Elem,_Traits>' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   c:\program files\microsoft visual studio 10.0\vc\include\ios(176) : see  declaration of 'std::basic_ios<_Elem,_Traits>::basic_ios' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
1>   This diagnostic occurred in the compiler generated function 'std::basic_ifstream<_Elem,_Traits>::basic_ifstream(const std::basic_ifstream<_Elem,_Traits> &)' 
1>   with 
1>   [ 
1>    _Elem=char, 
1>    _Traits=std::char_traits<char> 
1>   ] 
========== Build: 0 succeeded, 1 failed, 0 up-to-date, 0 skipped ========== 

可能是什麼我收到此錯誤的原因？代碼太長，無法發佈。 ，我使用的編譯器是微軟的Visual C++ 2010速成

編輯：

void HostelManager::guestMonitor() { 
     system("cls"); 

     cout << "Name of the guest : "; // cin guest 
     cin.ignore(); 
     getline(cin , guestName); 

     cout << "\nWhom to meet : "; // to whom the guest wants to meet 
     cin.ignore(); 
     getline(cin , fullName); 

     string pathGND = "d:/HostelManager/studentDetails/groundFloor/" + fullName + ".txt"; 
     string pathFST = "d:/HostelManager/studentDetails/firstFloor/" + fullName + ".txt"; 
     string pathSND = "d:/HostelManager/studentDetails/firstFloor/" + fullName + ".txt"; 
     ifstream checkStudentGND(pathGND); 
     ifstream checkStudentFST(pathFST); 
     ifstream checkStudentSND(pathSND); 
     string x = "Floor"; 

     if(checkStudentGND) { 
      ifstream readRoom(pathGND); 
      readRoom >> fullName >> fatherName >> permanentAddress >> postalAddress >> x >> roomNumberToBeAlloted_GND; 
      int hisRoomNumber = roomNumberToBeAlloted_GND; 
      readRoom.close(); 
      storeGuestData(hisRoomNumber , fullName); // call to store guest data 
     } else if(checkStudentFST) { 
      ifstream readRoom(checkStudentFST); 
      readRoom >> fullName >> fatherName >> permanentAddress >> postalAddress >> x >> roomNumberToBeAlloted_FST; 
      int hisRoomNumber = roomNumberToBeAlloted_FST; 
      storeGuestData(hisRoomNumber , fullName); // call to store guest data 
     } else if(checkStudentSND) { 
      ifstream readRoom(checkStudentSND); 
      readRoom >> fullName >> fatherName >> permanentAddress >> postalAddress >> x >> roomNumberToBeAlloted_SND; 
      int hisRoomNumber = roomNumberToBeAlloted_SND; 
      storeGuestData(hisRoomNumber , fullName); // call to store guest data 
     } else { 
      string sorryMSG = "Sorry ! The student is not in this hostel"     cout << sorryMSG << endl ; 
     } 
    } 

被調用的函數：

void HostelManager::storeGuestData(int hisRoomNumber , string hisName) { 
     cout << "\nVisitor's Address : "; // cin visitor address 
     string visitorAddress; 
     getline(cin , visitorAddress); 

     cout << "\nRelation with the student : "; // cin relation with student 
     string relation; 
     getline(cin , relation); 

     cout << "\nEnter Month"; // cin enter month 
     short month; 
     cin >> month; 

     cout << "\nEnter Date"; // cin enter date 
     short date; 
     cin >> date; 

     cout << "\nYou can meet " << hisName << " in room number " << hisRoomNumber << endl ; 

     string visitorPath = "d:/HostelManager/GuestMonitor/" + fullName + ".txt" ; 
     ofstream guestEntry(visitorPath); 
     guestEntry << "Name of Visitor : " << guestName << endl ; 
     guestEntry << "To meet : " << fullName << endl ; 
     guestEntry << "Address of visitor : " << visitorAddress << endl ; 
     guestEntry << "Relation with the student : " << relation << endl ; 
     guestEntry << "Month : " << month << endl ; 
     guestEntry << "Date : " << date << endl ; 
     guestEntry.close(); 
     cout << "\n\n\n\nData successfully inserted"; 
    } 

數據成員：

private: 
     string fullName; 
     string fatherName; 
     string permanentAddress; 
     string postalAddress; 
     int mobileNumbers[2][10]; 
     double percentageMarks; 
     int roomNumber; 
     int roomNumberToBeAlloted_GND ; 
     int roomNumberToBeAlloted_FST ; 
     int roomNumberToBeAlloted_SND ; 
     string preferredFloor; 
     string guestName; 
     string studentFined; 
     string complaintAgainst; 
     string receiverOfEmail; 
     string senderOfEmail; 
     string subject; 

    public: 
     void guestMonitor(); 
     void storeGuestData(int hisRoomNumber , string hisName); 

Answer 1

您正試圖複製流，這是不可能的。

爲了幫助您避免這種情況，其中一個基類具有私有拷貝構造函數。

Answer 2

從你的錯誤中，我可以猜測你試圖將operator <<或operator >>與fstream（或ostream）重載爲你自己的class對象。

不知怎的，你已經錯過一提的是operator <<功能朋友您class的。你的代碼應該是like this snippet。仔細查看數據成員爲目標class製作爲public。

Answer 3

違規的線條，

ifstream readRoom(checkStudentFST); 

，並

ifstream readRoom(checkStudentSND); 

，你要複製的，而不是或許與文件名打開它現有的流。

Answer 4

如果要設置一個類參數的構造函數（這是使對象的副本），這樣可能會出現問題：

class Test 
{ 
public: 
    Test() {} 
    Test(FileHandler fh_) : fh(fh_) {} 
    // ... 
private: 
    FileHandler fh; 
}; 

如果FileHandler類包含一個成員是一個文件流，你會得到錯誤，就像我一樣。

SOLUTION：將構造函數參數從FileHandler fh_更改爲FileHandler* fh_。