typedef struct Node {
	int key;
	struct Node *left, *right;
} Node;

/* function: inserts a new node to the tree
input: proot: pointer to the pointer to the tree root
x: the key of the new node
output: returns a pointer to the newly inserted node
returns NULL if insertion is not successful
*/
Node *insertNode(Node **proot, int x);

/* function: searches for a node in the tree
input: root: pointer to the tree root
x: the key of of the node to be searched
output: returns a pointer to the found node
returns NULL if no such node exists
*/
Node *findNode(Node *root, int x);

/* function: removes a node from the tree without freeing it
input: proot: pointer to the pointer to the tree root
x: the key of of the node to be deleted
output: returns a pointer to the deleted node
returns NULL if no such node exists
*/
Node *deleteNode(Node **proot, int x);

/* function: deletes all the nodes in the tree and frees the memory
   occupied by them
input: root: pointer to the tree node
output: none
*/
void destroyTree(Node *root);

/* function: prints the tree in ASCII
   (this function is already implemented in printTree.c)
input: root: pointer to the tree node
output: none
*/
void printTree(Node *root);