我在这个问题上进行了很多搜索,发现很多相似的问题,但是我没有找到解决方法。我要宣布一个类(class):

class File {

    public:
            string fileName;
            std::ifstream & flinstream;
            Password pass;
            //Next block to look at
            unsigned int nb;
            unsigned int sectorsLeft;
File (string name,string passd);
File ( );
};

和相应的功能:
File::File (string name,string passd) {
         fileName =  name;
        const char* cstr =  name.c_str();
         pass =  Password(passd);
         flinstream =  std::ifstream(cstr);
        if(!flinstream.good()) {
            string err =  "The file '";
            err.append(name);
            err.append("' could not be opened!");
            callError(err,3);
        }
    }

在编译时,出现以下错误:
 [0] => out.cpp: In constructor ‘File::File(std::string, std::string)’:
    [1] => out.cpp:130:3: error: uninitialized reference member ‘File::flinstream’
    [2] => In file included from /usr/include/c++/4.5/ios:39:0,
    [3] =>                  from /usr/include/c++/4.5/ostream:40,
    [4] =>                  from /usr/include/c++/4.5/iostream:40,
    [5] =>                  from out.cpp:1:
    [6] => /usr/include/c++/4.5/bits/ios_base.h: In member function ‘std::basic_ios<char>& std::basic_ios<char>::operator=(const std::basic_ios<char>&)’:
    [7] => /usr/include/c++/4.5/bits/ios_base.h:788:5: error: ‘std::ios_base& std::ios_base::operator=(const std::ios_base&)’ is private
    [8] => /usr/include/c++/4.5/iosfwd:77:11: error: within this context
    [9] => /usr/include/c++/4.5/iosfwd: In member function ‘std::basic_istream<char>& std::basic_istream<char>::operator=(const std::basic_istream<char>&)’:
    [10] => /usr/include/c++/4.5/iosfwd:83:11: note: synthesized method ‘std::basic_ios<char>& std::basic_ios<char>::operator=(const std::basic_ios<char>&)’ first required here
    [11] => /usr/include/c++/4.5/iosfwd: In member function ‘std::basic_ifstream<char>& std::basic_ifstream<char>::operator=(const std::basic_ifstream<char>&)’:
    [12] => /usr/include/c++/4.5/iosfwd:111:11: note: synthesized method ‘std::basic_istream<char>& std::basic_istream<char>::operator=(const std::basic_istream<char>&)’ first required here
    [13] => /usr/include/c++/4.5/streambuf: In member function ‘std::basic_filebuf<char>& std::basic_filebuf<char>::operator=(const std::basic_filebuf<char>&)’:
    [14] => /usr/include/c++/4.5/streambuf:781:7: error: ‘std::basic_streambuf<_CharT, _Traits>::__streambuf_type& std::basic_streambuf<_CharT, _Traits>::operator=(const std::basic_streambuf<_CharT, _Traits>::__streambuf_type&) [with _CharT = char, _Traits = std::char_traits<char>, std::basic_streambuf<_CharT, _Traits>::__streambuf_type = std::basic_streambuf<char>]’ is private
    [15] => /usr/include/c++/4.5/iosfwd:108:11: error: within this context
    [16] => /usr/include/c++/4.5/iosfwd: In member function ‘std::basic_ifstream<char>& std::basic_ifstream<char>::operator=(const std::basic_ifstream<char>&)’:
    [17] => /usr/include/c++/4.5/iosfwd:111:11: note: synthesized method ‘std::basic_filebuf<char>& std::basic_filebuf<char>::operator=(const std::basic_filebuf<char>&)’ first required here
    [18] => out.cpp: In constructor ‘File::File(std::string, std::string)’:
    [19] => out.cpp:134:36: note: synthesized method ‘std::basic_ifstream<char>& std::basic_ifstream<char>::operator=(const std::basic_ifstream<char>&)’ first required here
    [20] => out.cpp: In constructor ‘File::File()’:
    [21] => out.cpp:142:3: error: uninitialized reference member ‘File::flinstream’
    [22] => out.cpp: In member function ‘File& File::operator=(const File&)’:
    [23] => out.cpp:51:12: error: non-static reference member ‘std::ifstream& File::flinstream’, can't use default assignment operator
    [24] => out.cpp: In function ‘int main(int, char**)’:
    [25] => out.cpp:166:57: note: synthesized method ‘File& File::operator=(const File&)’ first required here
)

我已经收集到ifstream在分配和所有方面都相当特殊,但是我不知道如何在类中包含它。在此先感谢您的帮助!

编辑:我已经尝试了上述类的几种排列,例如使用普通变量:
std::ifstream flinstream;

以及使用建议的open()函数:
flinstream.open(cstr);

但是,错误保持不变。

最佳答案

对于初学者,除非您真的想要引用ifstream,否则我只在您的类中将ifstream声明为

std::ifstream flinstream;

在C++ 03(C++的早期版本)中,流类的分配被禁用,因此该行
flinstream =  std::ifstream(cstr);

不会编译。但是,您可以使用std::ifstream::open方法执行此操作:
flinstream.open(cstr);
/* ... remaining processing ... */

希望这可以帮助!

关于c++ - C++ ifstream类错误,我们在Stack Overflow上找到一个类似的问题:https://stackoverflow.com/questions/9123176/

10-11 22:38
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