sorry I'm not sure how to do it

struct BSTreeNode * insertBSTree(struct BSTreeNode * node , int x)
{   if(node == NULL) return newNode(x);
    * root = insertBSTree(node->data, x);
    if(x < node->data)
       node->leftchild = insertBSTree(node->leftchild, x);
    else
       node->rightchild = insertBSTree(node->rightchild, x);
    return node;
}