GCC and Copy Constructor

Have Problems to create a Copy Constructor
Several Tutorials later i didnt get it.
im using Dev C++ with gcc. i did it in the school some years ago with VS 6

should be:

Code:

---

class cX
{
private: float n;
public:
cX(){n=0.0;};
float GetN(){return n;};
cX(const cX& x){n=x->GetN();}; // <- COPY N!!
};

---

ERROR: passing `const cX' as `this' argument of `float cX::GetN()' discards qualifiers

any suggestions?

you have to tell the compiler that it's ok to call GetN() on a const object.

Code:

---

float GetN() const { return n; }

---

GetN should be declared const, i.e.,

Code:

---

class cX
{
private:
    float n;
public:
    cX()
    {
        n = 0.0;
    }

    float GetN() const
    {
        return n;
    }

    cX(const cX& x)
    {
        n = x->GetN();
    }
};

---

However, note that you do not need to define the copy constructor here as the compiler provided one will suffice. Hence:

Code:

---

class cX
{
private:
    float n;
public:
    cX() : n(0.0) {}

    float GetN() const
    {
        return n;
    }
};

---

Notice that I used the default constructor's initialiser list.

nice ill try that - thanks for super fast answer

really nice 4 hours searching and reding done in 15mins. THX again elkvis & laserlight RoX

Also please take note of Laserlight's formatting of the code. Yours is horrible.

Quote:

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Originally Posted by Elysia

Also please take note of Laserlight's formatting of the code. Yours is horrible.

---

I wouldn't call it horrible. I've seen much, much worse. It does; however, need improvement.

I've seen worse code, too, but the point is that even if it is worse than this, it is still horrible, because everything that even more horrible than horrible is still be horrible, too.
The quality of this code is not something you should see in a project. Hence, I would like to call it horrible, because it needs improvement.
(Anything more horrible than this is horrible, too, and thus also needs to be fixed.)