samples C/C++: fixed compilation problem on Ubuntu

samples/c/find_obj.cpp

@@ -12,6 +12,7 @@
 
 #include <iostream>
 #include <vector>
+#include <stdio.h>
 
 using namespace std;
 void help()

samples/c/find_obj_ferns.cpp

@@ -7,6 +7,7 @@
 #include <algorithm>
 #include <iostream>
 #include <vector>
+#include <stdio.h>
 
 using namespace cv;
 void help()

samples/c/mser_sample.cpp

@@ -6,6 +6,7 @@
 #include "opencv2/features2d/features2d.hpp"
 #include "opencv2/imgproc/imgproc_c.h"
 
+#include <stdio.h>
 
 void help()
 {

samples/c/one_way_sample.cpp

@@ -13,6 +13,8 @@
 #include "opencv2/imgproc/imgproc_c.h"
 
 #include <string>
+#include <stdio.h>
+
 void help()
 {
 	printf("\nThis program demonstrates the one way interest point descriptor found in features2d.hpp\n"

samples/cpp/calibration_artificial.cpp

@@ -1,14 +1,16 @@
+#include "opencv2/calib3d/calib3d.hpp"
+#include "opencv2/imgproc/imgproc.hpp"
+#include "opencv2/highgui/highgui.hpp"
+
 #include <iostream>
 #include <vector>
 #include <algorithm>
 #include <iterator>
-
-#include "opencv2/calib3d/calib3d.hpp"
-#include "opencv2/imgproc/imgproc.hpp"
-#include "opencv2/highgui/highgui.hpp"
+#include <stdio.h>
 
 using namespace cv;
 using namespace std;
+
 void help()
 {
     printf( "\nThis code generates an artificial camera and artificial chessboard images,\n"