Question

我运行时遇到以下错误。有什么帮助吗？

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

这是我在pp对象中的代码

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

这是我的主要内容

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

     pp pointObject();
     getfile >> point;
}

这是我的pp.h结构，你们想看看。

    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

operator>>不能是该类的成员，因为这会使参数的顺序错误。您必须考虑所有成员函数（和运算符）的隐式this参数。

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

Answer 2

operator >>的定义应为：

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

然后，在函数体内，您应该将读取的x和y值分配给p.x和p.y。

Answer 3

我建议写一个独立的运算符重载

注意，Re：处理流错误并使用例外，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

重载流运营商的最佳方法是让他们成为朋友。

在你的pp类声明中：

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

在你的cpp文件中：

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

运算符的模糊重载＆gt;＆gt;'in'getfile＆gt;＆gt;点'

4 个答案: