Program to prune binary search tree

prune_tree.c

#include<stdio.h>
#include<stdlib.h>
#include<math.h>

struct node{
        int value;
        struct node *left;
        struct node *right;
};
typedef struct node Node;

Node * prune_nodes(Node * root, int min, int max){

        if(root == NULL) return NULL;

        Node * root->left =  prune_node(root->left, min, max);
        Node * root->right = prune_node(root->right, min, max);

        if(root->value < min)
                Node * right_tree = root->right;
                free(root);
                return right_tree;
        }
        if (root->value > max){
                Node *left_tree = root->left;
                free(root);
                return left_tree;
        }
        return root;
}
Node * create_node(int value){
        Node * temp =  (Node *)malloc(sizeof(Node));
        temp->value = value;
        temp->right= NULL;
        temp->left = NULL;
}
Node * addNode(Node *node, int value){
        if(node == NULL){
                return create_node(value);
        }
        else{
          if (node->value > value){
                node->left = addNode(node->left, value);
          }
          else{
                node->right = addNode(node->right, value);
          }
        }
        return node;
}
 
/* Driver program for the function written above */
int main(){
        Node *root = NULL;
        Node * last = NULL;
        Node *ptrToHead = NULL;
        //Creating a binary tree
        root = addNode(root,30);
        root = addNode(root,20);
        root = addNode(root,15);
        root = addNode(root,25);
        root = addNode(root,40);
        root = addNode(root,37);
        root = addNode(root,45);
        
        prune_nodes(root, 22,40);       
        
        return 0;
}