diff --git a/a3/binary_search_tree.c b/a3/binary_search_tree.c
index 6d99c67..4f50c59 100644
--- a/a3/binary_search_tree.c
+++ b/a3/binary_search_tree.c
@@ -1,37 +1,53 @@
-#include <stdio.h>
+#ifndef BINARY_SEARCH_TREE_H
+#define BINARY_SEARCH_TREE_H
+
+#include <stddef.h>
+
+typedef struct node node_t;
+
+struct node {
+   node_t *right;
+   node_t *left;
+   int data;
+};
+
+node_t *build_tree(int *tree_data, size_t tree_data_len);
+void free_tree(node_t *tree);
+int *sorted_data(node_t *tree);
+
+#endif
+#include "binary_search_tree.h"
 #include <stdlib.h>
 
-typedef struct node {
-    struct node *right;
-    struct node *left;
-    int data;
-} node_t;
-
-
-node_t *insert_node(node_t *root, int data);
-void free_tree(node_t *tree);
-int *sorted_data(node_t *tree, int *count);
-void inorder_traversal(node_t *tree, int *arr, int *index);
-
-
-node_t *insert_node(node_t *root, int data) {
-    if (root == NULL) {
-        node_t *new_node = malloc(sizeof(node_t));
-        if (new_node == NULL) {
-            return NULL; 
-        }
-        new_node->data = data;
-        new_node->left = new_node->right = NULL;
-        return new_node;
-    }
-    if (data <= root->data) {
-        root->left = insert_node(root->left, data);
-    } else {
-        root->right = insert_node(root->right, data);
+node_t *new_node(int value) {
+    node_t *node = malloc(sizeof(node_t));
+    if (node != NULL) {
+        node->data = value;
+        node->left = NULL;
+        node->right = NULL;
     }
+    return node;
+}
+
+node_t *insert_node(node_t *root, int value) {
+    if (root == NULL)
+        return new_node(value);
+
+    if (value <= root->data)
+        root->left = insert_node(root->left, value);
+    else
+        root->right = insert_node(root->right, value);
+
     return root;
 }
 
+node_t *build_tree(int *tree_data, size_t tree_data_len) {
+    node_t *root = NULL;
+    for (size_t i = 0; i < tree_data_len; i++) {
+        root = insert_node(root, tree_data[i]);
+    }
+    return root;
+}
 
 void free_tree(node_t *tree) {
     if (tree != NULL) {
@@ -41,49 +57,19 @@ void free_tree(node_t *tree) {
     }
 }
 
-
-void inorder_traversal(node_t *tree, int *arr, int *index) {
+void tree_to_sorted_array(node_t *tree, int arr[], int *index) {
     if (tree != NULL) {
-        inorder_traversal(tree->left, arr, index);
-        arr[*index] = tree->data;
-        (*index)++;
-        inorder_traversal(tree->right, arr, index);
+        tree_to_sorted_array(tree->left, arr, index);
+        arr[(*index)++] = tree->data;
+        tree_to_sorted_array(tree->right, arr, index);
     }
 }
 
-
-int *sorted_data(node_t *tree, int *count) {
-    *count = 0;
-    inorder_traversal(tree, NULL, count);
-
-    int *arr = malloc(sizeof(int) * (*count));
-    if (arr == NULL) {
+int *sorted_data(node_t *tree) {
+    if (tree == NULL)
         return NULL;
-    }
-    int index = 0;
-    inorder_traversal(tree, arr, &index);
+
+    int *arr = malloc(100 * sizeof(int)); 
+    tree_to_sorted_array(tree, arr, &index);
     return arr;
 }
-
-int main() {
-    node_t *root = NULL;
-    int tree_data[] = {4, 2, 6, 1, 3, 5, 7};
-    int tree_data_len = sizeof(tree_data) / sizeof(tree_data[0]);
-
-    for (int i = 0; i < tree_data_len; i++) {
-        root = insert_node(root, tree_data[i]);
-    }
-
-    int count = 0;
-    int *sorted = sorted_data(root, &count);
-    
-    printf("Sorted data: ");
-    for (int i = 0; i < count; i++) {
-        printf("%d ", sorted[i]);
-    }
-    printf("\n");
-
-    free(sorted);
-    free_tree(root);
-    return 0;
-}
\ No newline at end of file