copy constructor of base and derived classes

Question

I have those two classes

///////////BASE CLASS

    class Base{
    public:
     Base(int = 0);
     ~Base();
     Base(Base&);
     Base(Derived&);   ////<-may be problem here?, note: I tried without this function
     int valueOfBase();
    protected:
     int protectedData;
    private:
     int baseData;
    };

    /////////////DERIVED CLASS
    class Derived: public Base{
    public:
     Derived(int);
     //Derived(Derived&);
     ~Derived();
    private:
     int derivedData;
    };

and here my main

    int main(){
     Base base(1);
     Derived derived = base;
    return 0;
    }

I read that if my derived class doesn't have copy c'tor copy c'tor of the base will be called but every time I receive conversion from Base to non-scalar type Derived requested who is wrong? my compiler or my book, or I've just misunderstood? thanks in advance

Answer 1

Just a hint.

Does the following code give the same error?

class base{};
class derived: public base{};

int main()
{
      derived d= base();
}

Yes? Why? Because there is no conversion from the base class to the derived class. You should define this conversion if you want your code to compile.

How about adding this to the derived class ?

derived(const base &b){} 

Makes sense, huh?