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/