问题描述
我试图声明一个ifstream对象在头文件,如显示,但我得到一个错误,说它不能访问。我已经尝试过各种各样的事情,如使它成一个指针,初始化在.c文件等,但我的代码似乎不能得到它的声明。
I am trying to declare an ifstream object in a header file as is shown but I get an error saying that it cannot be accessed. I have tried various things such as making it into a pointer instead, initialising in the .c file etc. but my code can't seem to get part the declaration of it.
ReadFile.h:
ReadFile.h:
#ifndef READFILE_H
#define READFILE_H
#include "cv.h"
#include "highgui.h"
#include <iostream>
#include <fstream>
class ReadFile{
private:
std::ifstream stream;
public:
std::string read();
ReadFile(); // Default constructor
~ReadFile(); // Destructor
};
#endif
ReadFile.c:
#include ReadFile.h
ReadFile.c: #include "ReadFile.h"
ReadFile::ReadFile(){
stream.open("./data.txt");
}
ReadFile::~ReadFile(){
stream.close();
}
我得到的错误是:
Error 9 error C2248: 'std::basic_ifstream<_Elem,_Traits>::basic_ifstream' : cannot access private member declared in class 'std::basic_ifstream<_Elem,_Traits>' c:\users\Bob\documents\project\models\readfile.h 23 1 Project
输出为:
1>c:\users\Bob\documents\project\models\readfile.h(23): error C2248: 'std::basic_ifstream<_Elem,_Traits>::basic_ifstream' : cannot access private member declared in class 'std::basic_ifstream<_Elem,_Traits>'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]
1> c:\program files (x86)\microsoft visual studio 11.0\vc\include\fstream(827) : see declaration of 'std::basic_ifstream<_Elem,_Traits>::basic_ifstream'
1> with
1> [
1> _Elem=char,
1> _Traits=std::char_traits<char>
1> ]
1> This diagnostic occurred in the compiler generated function 'ReadFile::ReadFile(const ReadFile &)'
当包含 std :: ifstream stream;
时会发生错误,并且在删除此行时将会消失。可能是什么原因导致此错误?
The error occurs when std::ifstream stream;
is included and will disappear when this line is removed. What could be causing this error? Have I missed something really obvious or is there more to it?
推荐答案
问题是 std: :ifstream
没有公共副本构造函数(因为复制一个构造函数没有意义),但是类的编译器生成的复制构造函数想要使用它。
The problem is that std::ifstream
doesn't have a public copy constructor (because copying one wouldn't make sense) but the compiler-generated copy constructor for your class wants to use it.
由于同样的原因,它没有任何可用的赋值运算符(即复制 std :: ifstream
是无意义的)。
It doesn't have any available assignment operator for the same reason (i.e. copying a std::ifstream
is nonsense).
一个简单的方法是添加
private:
ReadFile(const ReadFile&);
ReadFile& operator=(const ReadFile&);
。
在C ++ 11中,使用 = delete
语法。
In C++11, use the = delete
syntax.
public:
ReadFile(const ReadFile&) = delete;
ReadFile& operator=(const ReadFile&) = delete;
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