diff --git a/bintree.c b/bintree.c
index 4391f2a..7e60d61 100644
--- a/bintree.c
+++ b/bintree.c
@@ -55,10 +55,16 @@ TreeNode *addToTreeRec(TreeNode *currentNode, TreeNode *newNode, CompareFctType
     {
         if ((isDuplicate == NULL) || root)
         {
+            if (isDuplicate != NULL)
+            {
+                *isDuplicate = 0;
+            }
+            
             return newNode;
         }
         else
         {
+            *isDuplicate = 0;
             return currentNode;
         }
     }
@@ -82,7 +88,10 @@ TreeNode *addToTreeRec(TreeNode *currentNode, TreeNode *newNode, CompareFctType
         }
     }
 
-
+    if (isDuplicate != NULL)
+    {
+        *isDuplicate = 0;
+    }
     return currentNode;
 }