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Question

I am still new to C++ and as part of an assignment I have written a class that needs an overload of the stream extraction operator '>>' for file stream extraction in order to make things a bit easier, so says the instructions. I have declared and defined 2 overloads for both operators, one oveload for iostream objects and one overload for fstream object. Now, everything is fine until i get to the definition of '>>' for file stream objects, apparently that function has no access to the private (or protected) member of the class of which it is a friend of.

Here is my code, i thank you all in advance:

stock.h

#ifndef STOCK_H
#define STOCK_H
#include<iostream>
#include<fstream>


class Stock_Type 
{
    friend std::ostream& operator<<(std::ostream&, const Stock_Type&);
    friend std::istream& operator>>(std::istream&, Stock_Type&);
    friend std::ofstream& operator<<(std::ofstream&, const Stock_Type&);
    friend std::ifstream& operator>>(std::ofstream&, Stock_Type&);

    public:

        //constructor overloads-----------------------------------------------------------------------------------------------------
        Stock_Type(){};
        Stock_Type(std::string sym, double a, double b, double c, double d, double e, int f, double g) :
            stock_symbol(sym), opening_price(a), closing_price(b), high_price(c), low_price(d), prev_close(e), volume(f), percent_gain(g) {}

        //default destructor--------------------------------------------------------------------------------------------------------
        ~Stock_Type(){};

        //accessor functions--------------------------------------------------------------------------------------------------------
        void set_Symbol(std::string x){stock_symbol = x;}
        void set_Closing_Price(double x){closing_price = x;}
        void set_High_Price(double x){high_price = x;}
        void set_Low_Price(double x){low_price = x;}
        void set_Prev_Close(double x){prev_close = x;}
        void set_Volume(int x){volume = x;}

        std::string get_Stock_Smybol(){return stock_symbol;}
        double get_Opening_Price(){return opening_price;}
        double get_Closing_Price(){return closing_price;}
        double get_High_Price(){return high_price;}
        double get_Low_Price(){return low_price;}
        double get_Prev_Close(){return prev_close;}
        int get_Volume(){return volume;}
        double get_Percent_Gain_Loss(){return get_Closing_Price() - get_Opening_Price();}

        //operations on Stock_Type-------------------------------------------------------------------------------------------------------


        //operator functions--------------------------------------------------------------------------------------------------------------
        bool operator==(const Stock_Type&)const;
        bool operator!=(const Stock_Type&)const;
        bool operator<(const Stock_Type&) const;
        bool operator<=(const Stock_Type&)const;
        bool operator>(const Stock_Type&)const;
        bool operator>=(const Stock_Type&)const;
        friend std::ostream& operator<<(std::ostream&, const Stock_Type&);
        friend std::istream& operator>>(std::istream&, Stock_Type&);
        const Stock_Type& operator=(const Stock_Type &right_operand);

        Stock_Type& operator[](int elem);
        const Stock_Type& operator[](int elem) const;


    private:
        std::string stock_symbol;//record data1
        double opening_price, closing_price, high_price, low_price, prev_close;//record data2
        int volume;//record data3
        double percent_gain;//record data 4
        Stock_Type *stock_pointer;
        int array_size;


};





#endif

stock.cpp, i will only include the function for which an error is generated

std::ifstream& operator>>(std::ifstream& if_obj, Stock_Type& stock_obj)
{
    if_obj >> stock_obj.stock_symbol 
          >> stock_obj.opening_price
          >> stock_obj.closing_price 
          >> stock_obj.high_price
          >> stock_obj.low_price
          >> stock_obj.prev_close
          >> stock_obj.volume
          >> stock_obj.percent_gain;

    return if_obj;
}

the error is that for all the attributes that are listed are "inaccessible"

I'd like to finish this assignment as I'd like to move on to another one that is due on exception handling.

Thank you all in advance, once again.

Answer 1

i apologize, I believe that the signatures in the definition and implementation were different, as pointed out by a previous comment, i declared a friend function twice and there i saw my error, i did not change the code after copy/pasting it. For all future readers: MAKE SURE DECALRATION SIGNATURES MATCH IMPLEMENTATION SIGNATURES!

Answer 2

There is a

friend std::ifstream& operator>>(std::ofstream&, Stock_Type&);

but you have access problems in

std::ifstream& operator>>(std::ifstream& if_obj, Stock_Type& stock_obj)

Adding another friend should help.

friend std::ifstream& operator>>(std::ifstream& if_obj, Stock_Type& stock_obj);

Actually, you might prefer to edit the existing friend, it very much looks like a typo or other kind of trivial error.