Question

I’m trying to allocate dynamic memory to an array of objects, but I keep getting the following error:

“error: C2143: syntax error : missing ‘;’ before ‘*'”
“error: C2501: ‘Figura’ : missing storage-class or type specifiers”

Any help is welcomed. I’m using Visual Basic C++ 2006, but will switch to Turbo C++ 3.0 with Dosbox to get graphics.h working 🙁 .

Here’s the code:

#include<iostream.h>

class Grup {
    private:
        int nr_elemente;
        Figura *figuri;
    public:
        Grup() {
            figuri = new Figura[nr_elemente];
        }
};


class Figura {

public:
    Figura();
    ~Figura();
    Figura(const Figura&);

    friend Figura operator+(const Figura& fig1, const Figura& fig2) {};
    friend Figura operator+(const Grup& gr1, const Grup& gr2) {}

    friend Figura operator*(const Figura& fig) {}
    friend Figura operator*(const Figura& fig) {}

};

Figura operator+(const Figura& fig, const Grup& gr) {
    return fig;
}

class Punct : Figura
{
public:
    int x, y;

    Punct(int x, int y) {
        Punct::x = x;
        Punct::y = y;
    }
};

class Segment : Figura
{
public:
    int x, y, poz;
};

class Dreptunghi : Figura
{
public:
    int x, y, poz;
};

void main(void) {



}

Answer 1

In this line:

figuri = new Figura[nr_elemente];

The compiler does not know that a class Figura exists. Therefore, it generates an error, since “Figura” is an unknown token at that point. You should use a forward declaration:

class Figura; // forward-declare class Figura

class Grup {
/* ... */
};


class Figura {
/* ... */
};

The problem is that the compiler does not know the size of a class Figura, therefore it can’t allocate an array of objects of this type. Therefore you will probably need to use pointers or modify your class design.