diff --git a/bintree.c b/bintree.c
index 16eca55..cfe8571 100644
--- a/bintree.c
+++ b/bintree.c
@@ -72,8 +72,6 @@ TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFc
             *isDuplicate = 1;
     }
     return root;
-        
-    
 }
 
 // Iterates over the tree given by root. Follows the usage of strtok. If tree is NULL, the next entry of the last tree given is returned in ordering direction.
@@ -81,9 +79,22 @@ TreeNode *addToTree(TreeNode *root, const void *data, size_t dataSize, CompareFc
 // push the top node and push all its left nodes.
 void *nextTreeData(TreeNode *root)
 {
+    static StackNode *stack = NULL;
 
+    if (root != NULL)
+        stack = push_left(root, stack);
+
+    if (stack == NULL)
+        return NULL;
+
+    TreeNode *node;
+    node = pop(&stack);
+
+    if (node->right != NULL)
+        stack = push_left(node->right, stack);
+
+    return node->data;
 }
-
 // Releases all memory resources (including data copies).
 void clearTree(TreeNode *root)
 {