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

Node *insertNode(Node **proot, int x);
/*
 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 *deleteNode(Node **proot, 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 *findNode(Node *root, 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
*/

void destroyTree(Node *root);
/*
 function:
        deletes all the nodes in the tree and frees the memory occupied by them
 input:
        root - pointer to the tree node
*/

void printTree(Node *root);
/*
 function:
        prints ascii tree for given Node structure
        this function is already implemented in printTree.cpp
 input:
        root - pointer to the tree node
*/