C++: Storing class objects in a map (error: taking the address of a temporary object of type 'Node')

Question

I am trying to make a nodelist and I have two classes: Node & Nodelist. The constructor of Node looks like this:

Node::Node(int identifier, bool weighted){
    ID_ = identifier;
    numberOfConnections_ = 0;
    weighted_ = weighted;
}

When I try to add a connection between the nodes with this method:

void Nodelist::addOneWayConnection(int source, int target){
    connections_[source] = &Node(source, weightedlist_);    <-- error
    connections_[target] = &Node(source, weightedlist_);    <-- error
    connections_[source]->addConnection(connections_[target]);
}

I get the error:

error: taking the address of a temporary object of type 'Node'

How do I store a reference to the class Node?

Thanks in advance!

Answer 1

You don't want to store a reference to that. It ceases to exist after the expression. It's "temporary," as the error is telling you. You should either store Nodes directly, or store a pointer and use new to allocate them.

Edit: from your comment I've noticed that connections_ actually expects a pointer (as I said you could use above). You need to allocate new nodes.

connections_[source] = new Node(source, weightedlist_);
connections_[target] = new Node(source, weightedlist_);