diff --git a/tools/ping/client/main.cpp b/tools/ping/client/main.cpp
index bcef47a..d29549b 100644
--- a/tools/ping/client/main.cpp
+++ b/tools/ping/client/main.cpp
@@ -1,6 +1,6 @@
 /* -*- Mode:C++; c-file-style:"gnu"; indent-tabs-mode:nil; -*- */
 /*
- * Copyright (c) 2014-2023,  Arizona Board of Regents.
+ * Copyright (c) 2014-2024,  Arizona Board of Regents.
  *
  * This file is part of ndn-tools (Named Data Networking Essential Tools).
  * See AUTHORS.md for complete list of ndn-tools authors and contributors.
@@ -32,6 +32,8 @@
 #include <boost/program_options/parsers.hpp>
 #include <boost/program_options/variables_map.hpp>
 
+#include <iostream>
+
 namespace ndn::ping::client {
 
 class Runner : noncopyable