47 memory leaks. STL pointers.

Question

I have a major amount of memory leaks. I know that the Sets have pointers and i cannot change that! but clean up the mess i have...

I am creating memory with new in just about every function to add information to the sets.

here is my potential leaks..

library.cpp

#include "Library.h"
#include "book.h"
#include "cd.h"
#include "dvd.h"

#include <iostream>
// general functions


ItemSet allBooks;
ItemSet allCDS;
ItemSet allDVDs;




ItemSetMap allBooksByAuthor;
ItemSetMap allmoviesByDirector;
ItemSetMap allmoviesByActor;

ItemSetMap allMusicByBand;
ItemSetMap allMusicByMusician;



    const ItemSet* Library::itemsForKeyword(const string& keyword) const
    {


    const StringSet* kw;

    ItemSet* obj = new ItemSet();  
    return obj;


    const Item* Library::addBook(const string& title, const string& author, const int nPages)
    {

    ItemSet* obj = new ItemSet();
    Book* item = new Book(title,author,nPages);
    allBooks.insert(item); // add to set of all books
    obj->insert(item);

    return item;

Do, i need a copy constructor?

Answer 1

If you pass around pointers, you are responsible for them. Since you refuse to stop using pointers in Sets yourself, one solution would be to use smart pointers.

Answer 2

The thing with pointers is that every time you make a new Anything() then you need to make sure that something will eventually delete() that pointer. Take a step back and think about the life cycle of your new object. Take a look at every time you call new and think to yourself - what class is going to call delete on that pointer?

From the header file it doesn't look like your Library class has any members? One place to start might be to store the pointers from your new()'s there in some fashion, instead of the global?

You make a few calls to ItemSet* obj = new ItemSet(); That's one source of memory leak - the function will go out of scope and you lose the chance to call delete obj forever.

Also make your base class destructors virtual.

http://www.parashift.com/c++-faq-lite/virtual-functions.html#faq-20.7