Private Variable Compile Error: Variable is Private

Question

I have the following code:

class Point{
private:

    double x, y;
public:
    Point(){
        this->x = 0;
        this->y = 0;

    }
//...
};

I am getting an error on the private declaration of doubles x and y:

'double Point::y' is private

My code works fine when I rearrange it as:

class Point{
//private:
public:

    double x, y;
    //public:
    Point(){
       this->x = 0;
       this->y = 0;

    }   
//...
};

But obviously then double isn't private. If no private keyword is given and the doubles are declared before the public keyword, I get the same private variable error.

What am I doing wrong / how can I declare private variables properly? Thanks!

I have error makers in eclipse both within the class and at the declaration of the doubles: (I placed an X in the code since I can't post screen shots)

class Point{
private:
//public:

    X double x, y;
    X Point(): x{0},y{0}{
}

SOLVED: Thanks to Dieter Lücking for point out that in my example I forgot to uncomment the public keyword when I provided a full code example. Further along in my code I had written:

cout << "\nPoint sum: " << e.x + e.getY();

This, oddly, caused errors to appear both on the cout line, as well as the declaration line, which is what caused my confusion. Fixing the cout line:

cout << "\nPoint sum: " << e.x + e.getY();

Solved all the errors. Thank you all!

Answer 1

The most important thing to notice is that in your main function you try to access x and y directly instead of using the accessor functions getX() and getY().

Another thing is that (probably due to recent editing) all of your member functions in Point are private. Just uncomment the //public: line directly before the c'tor.

Answer 2

The code shown at the time of writing this answer isn't the problem.

The compiler complains about some other code accessing private members of a Point instance.

For a simple Point class, with no special class invariant, making the members public is a good idea, but note that in general it's not a good idea.

---

Since you have x and y members of type double, note that at least some not-very-long-ago version of Visual C++ had problems optimizing expressions involving such values accessed via accessor methods in a derived class. I don't know why. But it's an addition practical reason to make those members public.

Answer 3

In the function templateTestSum() you are accessing the private members x and y of point:

cout << "\nPoint sum: " << e.x + e.y;

This is not allowed.