How to delete a nary tree ? each node has a parent pointer too in it

Question

The structure of the node is below.

struct node
{
   int data;
   int noofchilds;
   node *child[n];
   node *parent;
 };

I would appreciate both recursive and non-recursive approaches.

Answer 1

Non-recursive version:

struct node {
    struct node *parent;
    unsigned nchild;
    struct node *child[XXX];
    int data;
    };

void deltree(struct node *np)
{
struct node *par;

while (np) {
        /* if this node has any children, start by
        ** "descending" to the highest numbered child and kill that first.
        */
        if (np->nchild--) {
                np = np->child[np->nchild];
                continue;
                }
        /* when we arrive here, *np has no more children left,
        ** so kill it, and step up to its parent
        */
        par = node->parent;
        // if np->child was obtained via malloc() uncomment next line
        // free (np->child);
        free (np);
        np = par;
        }
return;
}