diff --git a/samples/cpp/letter_recog.cpp b/samples/cpp/letter_recog.cpp
index 353440154e..fd75712a49 100644
--- a/samples/cpp/letter_recog.cpp
+++ b/samples/cpp/letter_recog.cpp
@@ -1,6 +1,7 @@
 #include "opencv2/core/core_c.h"
 #include "opencv2/ml/ml.hpp"
 
+#include <cstdio>
 /*
 The sample demonstrates how to train Random Trees classifier
 (or Boosting classifier, or MLP - see main()) using the provided dataset.
diff --git a/samples/cpp/watershed.cpp b/samples/cpp/watershed.cpp
index 0eaab6efd0..088c3f445e 100644
--- a/samples/cpp/watershed.cpp
+++ b/samples/cpp/watershed.cpp
@@ -1,6 +1,7 @@
 #include "opencv2/imgproc/imgproc.hpp"
 #include "opencv2/highgui/highgui.hpp"
 
+#include <cstdio>
 #include <iostream>
 
 using namespace cv;