int LeafIt(Tree *t)
// precondition: t != NULL
{
    if (t->left != NULL && t->right != NULL){
	return 1;
    }
    else return 0;

    // return t->left != NULL && t->right != NULL ? 1 : 0;
}


int TreeProduct(Tree * t)
{
    if (t == NULL){
	return 0;      // required by postcondition
    }
    else{
	int prod = t->info;
	int child = t->firstChild;
	while (child != NULL){
	    prod *= TreeProduct(child);
	    child = child->sibling;
	}
	return prod;
    }
}


void Quicksort(Dlist * & list)
{
    if (list != NULL){
	//partition list into two parts
	Dlist * hold;
	Pivot(list,hold);
	
	    // note:  all nodes in list are less than hold->info
	    //        and hold->info is smallest value in hold
	    //        (see spec. for Pivot)
	
	Dlist * anchor = hold;
	hold = hold->next;
	anchor->next = NULL;  
	
	Quicksort(list);
	Quicksort(hold);
	
	    // connect things back so that list is sorted>

	anchor->next = hold;       // second half now ok
	
	Dlist * first = list;
	if (first != NULL){
	    while (first->next != NULL){
		first = first->next;
	    }
	    first->next = anchor;
	}
	else{
	    list = anchor;
	}
    }
}