CODEWITHSUNDEEP
c++
jonnywalkerr
jonnywalkerr

Reputation: 157

Deleting objects using iterator

I am writing some code for a class project. One of the tasks is to delete a collection of pointers to a class we have created. The solution looks like this:

CDocument::~CDocument()
{
    for(std::list<CActor*>::iterator it = mActors.begin(); it != mActors.end(); it++)
    {
        delete *it;
    }

    mActors.clear();

}

My solution looked like this:

CDocument::~CDocument()
{
    for(std::list<CActor*>::iterator it = mActors.begin(); it != mActors.end(); it++)
    {
        delete **it;
    }
}

My confusion stems from dereferencing the iterator. I want to delete the CActor objects from the list. The iterator provides me, in this case, with a pointer to a pointer. Why would I delete the CActor pointer, *it, rather than the actual object in memory, **it? Also, why the additional mActors.clear()?

Upvotes: 2

Views: 408

Answers (1)

David Brown
David Brown

Reputation: 13526

Because delete operates on pointers, not the object itself or a reference to the object.. For example with the code

int* a = new int;

you would delete a with

delete a;

not

delete *a;

As for why mActors.clear(); is there, it's not strictly necessary since the std::list destructor will automatically do the same thing. However if more code is ever added to the destructor, clearing the list ensures all those dangling pointers cannot be accidentally used later.

Upvotes: 3

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