运营商的ambigious过载>>'在'getfile >>点'

Question

当我运行此操作时，我不断收到以下错误。任何帮助？

ambigious overload for ‘operator >> ’ in ‘getfile >> point’ 

这是我在第对象代码

istream& pp::operator >> (istream& in) 
{ 
    //error msg 
    string msg = "Error. Output from file, String is found instead of integer. Please check file for errors\n"; 

    //ignore everything till next record 
    in.ignore(256, '['); 

    //store x cordinate 
    in >> x; 
    if(in.fail()){throw msg;} 

    //ignore everything till next record 
    in.ignore(256, ','); 

    //store y cordinate 
    in >> y; 
    if(in.fail()){throw msg;} 

    //ignore the rest of the records till next line 
    in.ignore(256, '\n'); 

    return in; 

}//end of operator >> method 

这是我的主要

{ 
    ifstream getfile; 
    //get filename to input data into system 
    cout << "\nPlease enter filename : "; 
    cin >> file; 
    getfile.open(file, ios::in); 

    pp pointObject(); 
    getfile >> point; 
} 

这是我pp.h结构，其中你们希望看到的。

class pp 
    { 
    public: 
    //constructor 
    pp(); 
    pp(int, int); 
    pp(const Point2D &pd); 

    //operator overloaded methods 
    virtual pp operator-(pp pd); 
    virtual bool operator<(pp pd) const; 
    virtual bool operator>(pp pd) const; 
    virtual bool operator==(pp pd); 
    virtual ostream& operator<<(ostream& o) const; 
    virtual istream& operator>>(istream& in;  

    //accessor,mutator methods 
    int getX() const; 
    int getY() const; 

    void setX(int); 
    void setY(int); 

    protected: 
    int x; 
    int y; 
    }; 
    #endif 

Answer 1

的operator>>不能是类的成员，因为这样可以给它以错误的顺序的参数。您必须考虑所有成员函数（和运算符）的隐含this参数。

签名应该是istream& operator>>(istream& in, pp& point)，以便在getfile >> point;中使用它。

Answer 2

的定义您operator >>应该是：

istream& operator>>(istream& in, pp &p) 

然后，在函数体，你应该指定读p.x和p.y的x和y值。

Answer 3

我建议写一个独立的运算符重载

注意也回复：处理流错误和使用异常，请参阅try/catch throws error

friend istream& pp::operator>> (istream& in, pp& pointObject) 
{ 
    //error msg 
    const string msg = "ErPoint2Dror. Output from file, String is found instead of integer. Please check file for errors\n"; 

    //ignore everything till next record 
    in.ignore(256, '['); 

    int x,y; 

    //store x cordinate 
    in >> x; 
    if(in.fail()) 
    { 
     throw msg; 
    } 

    //ignore everything till next record 
    in.ignore(256, ','); 

    //store y cordinate 
    in >> y; 
    if(in.fail()) 
    { 
     throw msg; 
    } 

    //ignore the rest of the records till next line 
    in.ignore(256, '\n'); 

    pointObject.x = x; 
    pointObject.y = y; 

    return in; 
}//end of operator >> method 

Answer 4

重载流运营商最好的办法是保持他们作为朋友。

在你的PP类声明：

friend istream& operator >>(istream& in, pp& obj); 

在你的CPP文件：

istream& operator>>(istream &in, pp& obj) 
{ 
    // Your code 
}