From 492a101160f15a38f3e7447f64dce1783288c87a Mon Sep 17 00:00:00 2001
From: D2A62006 <david06.bruenner@gmail.com>
Date: Sun, 7 Dec 2025 21:26:44 +0100
Subject: [PATCH] Fix nextTreeData

---
 bintree.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/bintree.c b/bintree.c
index 82791ee..c0e47c8 100644
--- a/bintree.c
+++ b/bintree.c
@@ -77,12 +77,14 @@ void *nextTreeData(TreeNode *root)
         current = root;
     }
 
-    while (current != NULL)
-    {
+    while (current != NULL){
         stack = push(stack, current);
         current = current->left;
     }
 
+    if(stack == NULL){
+        return 0;
+    }
     TreeNode *node = (TreeNode *)top(stack);
     stack = pop(stack);