Question

A mate of mine told me, I’ve a memory leak in this code

Base
{
    public:
        vector<Foo*> fooes;
};

Derived : public Base
{
    public:

        Derived ( )
        {
            for ( int i = 0 ; i < 10 ; i++ )
            {
                    this.fooes.push_back ( new Foo() );
            }
        };

};

But he is a very busy man and he can not help me, so I ask you, where is the memory leak? And how do I fix it?
As I understand it, the memory leak is that I do not delete objects, created by new Foo(), so I just can add a destructor to Base, and clear fooes vector, right?

Base
{
    public:
        vector<Foo*> fooes;
        ~Base ( )
        {
            this->fooes.clear();
        };

};

The question is:

1. Is this a correct memory leak fix?

2. Will the destructor of Base be called before the destructor of Derived, or not?

3. Will the fooes vertor be deleted automatically while deleting Base or I must delete all members of the class manually?

Answer 1

1) Is this a correct memory leak fix?

No, you have to iterate through the elements and manually delete them.

2) Will the destructor of Base be called before the destructor of Derived, or not?

No (assuming you’re deleting a Derived object).

3) Will the fooes vector be deleted automatically while deleting Base or I must delete all members of the class manually?

Yes & no. The vector itself will be deleted because it is managed automatically, its members will not:

~Base ( )
{
   for ( size_t i = 0 ; i < fooes.size() ; i++ )
     delete fooes[i];
};

You should have a delete and delete[] for every new and new[] respectively.

A better alternative to all this is using smart pointers.