Find kth number in a BST

Find kth number in a BST

struct Node{	Node *left;	Node *right;	int val;	Node(int v) : val(v), left(NULL), right(NULL){}};void visit(Node *node, int &k, Node **p){	if (node == NULL)	{		return;	}	visit(node->left, k, p);	if (k == 0)	{		return;	}	k--;	if (k == 0)	{		*p = node;		return;	}	visit(node->right, k, p);}Node* findKthElement(Node *node, int k){	Node *p = NULL; 	visit(node, k, &p);	return p;}