diff --git a/contents/tree_traversal/code/cpp/tree_example.cpp b/contents/tree_traversal/code/cpp/tree_example.cpp
index 71a84c686..90271b58d 100644
--- a/contents/tree_traversal/code/cpp/tree_example.cpp
+++ b/contents/tree_traversal/code/cpp/tree_example.cpp
@@ -11,7 +11,7 @@ using std::size_t;
 
 struct node {
   std::vector<node> children;
-  int value;
+  size_t value;
 };
 
 // Simple recursive scheme for DFS