Thread: Derived class can't declare

Ok, somehow i think this is weird. I'm gonna summarized my whole code:

Code:

class Sphere;
class Rectangle;
class Segment;


class Body
{
   public: 
   vect2 Velocity, Position;
   float mass
     Body(){}
     //then other stuff and functions will go on
   //I also have some virtual bool function in here named "Collision"
};

class Sphere: public Body
{
public:
   float Radius;
   Sphere(){}
   //Then the collision functions will go on

};

So that's basically it. Then when i tried to do this:

Code:

Sphere ball;

it gave an error like this:

Code:

error C2259: 'Sphere' : cannot instantiate abstract class due to following members:
see declaration of 'Sphere'

Can someone help me out here?

EDIT: post removed because I realized that what I suggested would not work/make a difference.

Try this

Sphere ball = new body;

Among other things... Make the base destructor virtual... if you have one.. Nothing else I can think of with the code given..

Are you overriding all your pure virtual functions, like the collision ones?

Originally Posted by ichijoji

Are you overriding all your pure virtual functions, like the collision ones?

No, not that i know now. I was thinking about it but stuck with the derived class

@Shamio
It still give me the same error with your method.

Got it, i have to use pointer.

Yeah, I ment to put this:

Sphere * ball = new body;

Originally Posted by Shamino

Yeah, I ment to put this:

Sphere * ball = new body;

Don't you mean Body* ball = new Sphere(); ?
A body is not (neccessarily) a sphere!

@Shamio:
It's still giving me same error but with the Body class.

So, pointer is not working, can anyone have any suggestions?

Paste all the code...

bool Collision(const Rect& rRect, Event& eEvent, float& tMax) const;

Sphere doesn't implement this pure virtual method!

Nevermind, i forgot to put the '&' sign in the virtual function for "float& tMax" in the Body class. Everything is ok now.