Question

I am told I have to define an assignment operator for my Bullet class, however I was under the impression that the only time you really needed to implement the rule of three was when you explicitly handle memory yourself, such as a pointer class member.

I am actually told that the line that is attempting to invoke the operator= is std::vector<Bullet> bullets in the following code. I just don’t understand where the assignment operator is being called, and why it’s being called. Nowhere am I doing something like Bullet bullet1 = bullet2;

EDIT – and also, why isn’t the default assignment operator suitable? I have no pointer members anywhere in Bullet’s hierarchy.

Thanks for the help.

#ifndef GUN_H
#define GUN_H

#include "gameObject.h"
#include "Bullet.h"
#include <vector>

class Mesh;

class Gun : public GameObject
{  
    private:
        std::vector<Bullet> bullets; // this line right here

protected:
        virtual void TriggerPulled() = 0;

public:
        Gun(Mesh& mesh);

        virtual ~Gun();

    std::vector<Bullet>& Bullets();
};

#endif

this is the source for the same file:

#include "Gun.h"
#include "Mesh.h"

Gun::Gun(Mesh& mesh) : GameObject(mesh)
{
    bullets = std::vector<Bullet>();
}

Gun::~Gun() {}

std::vector<Bullet>& Gun::Bullets()
{
return bullets;
}

this is bullet:

#ifndef BULLET_H
#define BULLET_H

#include "BoundingSphere.h"
#include "helperMethods.h"
#include "GameObject.h"

class Bullet : public GameObject
{
private:
float velocity;
float distance;
D3DXVECTOR3 firedFrom;
BoundingSphere bSphere;

public:
Bullet(D3DXVECTOR3 position, D3DXVECTOR3 rotation, float velocity, D3DXCOLOR colour, Mesh&  mesh);
~Bullet();

BoundingSphere& BulletSphere();
};

#endif

BoundingSphere:

#ifndef BOUNDING_SPHERE_H
#define BOUNDING_SPHERE_H

#include <d3d10.h>
#include <d3dx10.h>

class Ray;
class BoundingBox;

class BoundingSphere
{
private:
D3DXVECTOR3 centre;
float radius;
public:
BoundingSphere(D3DXVECTOR3 position, float radius);
BoundingSphere();
bool Intersects(BoundingSphere boundingSphere);
bool Intersects(BoundingBox boundingBox);
bool Intersects(Ray ray, D3DXVECTOR3& result);

// getters
const D3DXVECTOR3 Centre();
const float Radius();

// setters
void BoundingSphere::Centre(D3DXVECTOR3 centre);
};

#endif

gameObject:

#ifndef GAMEOBJECT_H
#define GAMEOBJECT_H

#include <d3d10.h>
#include <d3dx10.h>

class Mesh;

class GameObject 
{
private:
D3DXVECTOR3         scale;
D3DXVECTOR3         rotation;
D3DXVECTOR3         position;
D3DXCOLOR           colour;

D3DXMATRIX matFinal;

Mesh& mesh;

protected:
void Draw(D3DMATRIX matView, D3DMATRIX matProjection);

public:
    GameObject(Mesh& mesh);
virtual ~GameObject();

//getters
const D3DXVECTOR3   Scale();
const D3DXVECTOR3   Rotation();
const D3DXVECTOR3   Position();
const D3DXCOLOR     Colour();

//setters
void Scale(D3DXVECTOR3 scale);
void Rotation(D3DXVECTOR3 rotation);
void Position(D3DXVECTOR3 position);
void Colour(D3DXCOLOR colour);
};

#endif

Answer 1

In the source you have:

bullets = std::vector<Bullet>();

The default = operator won’t work because GameObject has a reference member mesh which can’t be assigned to. (It’s almost like a pointer. It holds an address to an actual class or structure)