How to search a tree(postorder) in C

I write a function to search a tree, and find out the node suitable and store them in an array. It is in postorder.

void search_for_node(node *root, node *list[])
{
	int j;
	if (root == NULL)
		return;
	
	
	for(j=0; j<root->num_children; j++)
		search_for_node(root->children[j], list);
	if (root->type == ID)
	list[num_for++] = root;

	
	
}

But it can't work. Is there anything wrong in my code?
Thanks in advance!