Re: Distinguish between pointers created with 'new' and created with references.

On Jul 15, 8:03 am, dailos <dailos.guerr...@gmail.com> wrote:


1. a container of references can't be created, only containers of
pointers, so that makes your problem easier
2. yes you will need to delete the vector of fruit pointers to avoid
mem leak
3. make Fruit base class have a virtual destructor, that way when it
goes out of scope the destruct logic will propagate to each derived
class
4. make Basket destructor delete the mem of each Fruit pointer, then
clear the vector itself
5. FYI, using Boost shared_ptr instead to hold the Fruit pointers will
help avoid mem leak if exception is thrown after creating the
container and before calling deletes

Example code below:

class Fruit
{
public:
   virtual string name() = 0;
   virtual ~Fruit() {};
};

class Orange : public Fruit
{
public:
   virtual string name(){return string("Orange");};
   ~Orange() { cout << "Deleting Orange\n"; }

};

class Watermelon : public Fruit
{
public:
   virtual string name(){return string("Watermelon");};
   ~Watermelon() { cout << "Deleting Watermelon\n"; }

};

class Apple : public Fruit
{
public:
   virtual string name(){return string("Apple");};
   ~Apple() { cout << "Deleting Apple\n"; };

};

class Basket
{
public:

   ~Basket() {
       cout << "Bakset Destructor\n";

            // this loop can be avoided if you use Boost's shared_ptr
to hold the elements instead of regular
            // pointers as they will auto delete themselves, but
deleting these pointers still needs to be
            // done either way.
       for(vector<Fruit*>::iterator i = fruitList.begin(); i !=
fruitList.end(); i++)
       { delete *i; }

       fruitList.clear(); // without this the size will still be 3

       cout << fruitList.size();

   }

   void addFruit(Fruit* pFruit);
private:
   vector<Fruit*> fruitList;

};

void Basket::addFruit(Fruit* pFruit)
{
   fruitList.push_back(pFruit);
}

int main()
{
   Basket myBasket;
   myBasket.addFruit(new Watermelon());
   myBasket.addFruit(new Orange());
   myBasket.addFruit(new Apple());

   return 0;
}

-----------------------------
Bakset Destructor
Deleting Watermelon
Deleting Orange
Deleting Apple
0

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