Question

In class Node:

class Node {
public:
    int data;
    int numchild;  
    Node** nodelist;

    Node(int data, int s);
};

I want an array of pointers (nodelist) to other nodes, which have edges from this node.

Is the following way of constructing such an array (and the above way of declaring it) a correct and the best (or easiest) way possible? If not, why and whats the best way?

Node::Node(int d, int s) {
    data = d;
    numchild = s;
    nodelist = new Node*[s];
}

Answer 1

Generally you shouldn’t reinvent the wheel. Raw arrays are almost always the wrong way to go. Have a look at the various containers from the STL, i.e. std::vector, std::list. I woud guess that in your case a std::vector might be the best solution.

If you want to stick with the raw array, a quick warning: new Node*[s] does not initialize the array, so the contents will be undefined. But if you add a set of parentheses (new Node*[s]()) it will be initialized to zero which is a good thing as it helps you spot which entries have been filled already.

Also, your current code lacks a destructor to delete[] the nodelist again. That’s exactly why the use of standard containers is recommended: they have destructors that will do the work for you.