Question

I’m currently having trouble with a destructor of a class which contains a vector of objects. The application runs fine, however upon freeing the heap it throws an error.

Here is the code of my destructor:

    ~StaticNetwork(void) { // clear memory
    for(vector<Node*>::iterator iter = nodes.begin(); iter != nodes.end(); )
        nodes.erase(iter++);
}

And nodes are being added to the network as follows:

    if((temp = is_already_added(regex_d[1])) >= 0) // check if the src node has already been added
            {
                if((temp1 = is_already_added(regex_d[2])) >= 0) // check if the next_hop has already been added
                {
                    nodes[temp]->add_n_vchannels(regex_d[5]);
                    nodes[temp]->add_next_hop(nodes[temp1]);
                }
                else // the next_hop has not been added 
                {
                    Node *anext_hop = new Node(regex_d[2]);

                    nodes[temp]->add_next_hop(anext_hop);
                    nodes[temp]->add_n_vchannels(regex_d[5]);

                    nodes.push_back(anext_hop); //  add next hop        
                    param.n_of_nodes++;
                }       
            }

The network is comprised of pointers to the actual nodes.

Any help/suggestion/reference/(constructive)criticism will be greatly appreciated.

Answer 1

Your iteration over the container is wrong. If the node is a member of the class, then ignore it as the destructor of the vector will take care of it. If it is not a member and you really want to remove all elements, the simplest thing is calling node.clear() (Note both are equivalent to your code, but they will leak the pointed memory if it should be managed by your class)

If the pointers are managed by your class, consider using smart pointers or specific pointer containers. Else the simplest loop to free all memory would be:

for ( std::vector<Node*>::iterator it = nodes.begin(); it != nodes.end(); ++it )
   delete *it;

Note that I did not modify the container itself, just the contained elements.