Derived class does not have access to inherited function?

I'm creating a very simple program that involves inheritance. I put a function into the "protected" area of the parent class, and now I don't have access from the child class. Here is my code:

class Product : protected Item 
{

private:

    double Price;

protected:

    double getPrice(){return Price;}


//other code not connected
};

Later on, I derive:

class Toy : protected Item
{

// class Toy code that does not mention getPrice() at all

 };

And after that, I derive another class in which I actually try to use the getPrice() function.

In the new class's header file:

class Game : protected Toy
{

  double printGame(){return getPrice();}
};

This line does not give me an error.

But in the file game.cpp:

ostream& operator << (ostream& Output, const Game &printedGame)
{
 return Output 

 << "The game price is: "

 //This is the problem line

 << printedGame.printGame开发者_高级运维()

 << "." ;
 }

The word "printedGame" returns me "Error: the object has type qualifiers that are not compatible with the member function"

When I tried going directly (which I tried before, as such:)

printedGame.getPrice()

I get that error, and an additional one informing me that the getPrice() function is not accessible.

Any help here? Thanks!!

Your << operator is called with a const Game & object which means that the function may only call const member functions of Game

Add const to getPrice and printGame:

double getPrice() const {return Price;}
double printGame() const {return getPrice();}

You'll also have to make printGame public.

The getPrice() method is a member of Product, not Item. So deriving Toy from Item will not give it access to getPrice(). It would have to derive from Product (or one of its sub-classes.)

getPrice is accessible to members of Game, but your operator<< is not a member, nor should it be.

Instead, use a friend declaration to give operator<<(ostream&, const Game&) access.

class Product : protected Item 
{

private:

  double Price;

protected:

  double getPrice() const {return Price;}
};

class Toy : protected Product
{
};

class Game : protected Toy
{
  friend ostream& operator<<(ostream&, const Game&);
};

ostream& operator << (ostream& Output, const Game &printedGame)
{
  return Output 

   << "The game price is: "

   //This is the problem line

   << printedGame.getPrice()

   << "." ;
}

getPrice() method is a member of Product class but you derive from Item.

Also - if you would call it like that then I believe you need a const function to call in Product class

I took a stab at this, but had to make some assumptions to make it work. As written, the code should work

#include <iostream>

using std::ostream;

// I added this to make sure it looks close to your stated problem
class Item
{
};

class Product : protected Item 
{
private:    
    double Price;
protected:   
    // getter needs to be const, for the ostream operator to work
    double getPrice() const
    {
        return Price;
    }
};

// I changed this to derive from Product, otherwise, there's no inheritance tree.
// Is this what you intended to do?
class Toy : protected Product
{
};

class Game : protected Toy
{  
    // if you don't specify an access modifier, C++ defaults to private
public:
    // getter needs to be const, for the ostream operator to work
    double printGame() const
    {
        return getPrice();
    }
};

ostream& operator << (ostream& Output, const Game &printedGame)
{
    return Output  << "The game price is: " << printedGame.printGame() << "." ;
}

int _tmain(int argc, _TCHAR* argv[])
{
    return 0;
}