adding headers and output

example_02-02.cpp

@@ -1,8 +1,26 @@
+// Example 2-2. Same as Example 2-1 but employing the “using namespace” directive
+
 #include "opencv2/highgui/highgui.hpp"
+#include <iostream>
 
 using namespace cv;
 
+void help(char** argv ) {
+	std::cout << "\n"
+	<< "2.2: Like 2.1, but 'using namespace cv: \n"
+	<< argv[0] <<" <path/image>\n"
+	<< "For example:\n"
+	<< argv[0] << " ../fruits.jpg\n"
+	<< std::endl;
+}
+
+
 int main( int argc, char** argv ) {
+
+	if (argc != 2) {
+		help(argv);
+		return 0;
+	}
 
   Mat img = imread( argv[1], -1 );
 

example_02-03.cpp

@@ -1,10 +1,26 @@
+// Example 2-3. A simple OpenCV program for playing a video file from disk
+
 #include "opencv2/highgui/highgui.hpp"
 #include "opencv2/imgproc/imgproc.hpp"
 #include <iostream>
 
 using namespace std;
+void help(char** argv ) {
+	std::cout << "\n"
+	<< "2-03: play video from disk \n"
+	<< argv[0] <<" <path/video>\n"
+	<< "For example:\n"
+	<< argv[0] << " ../tree.avi\n"
+	<< std::endl;
+}
+
 
 int main( int argc, char** argv ) {
+
+	if (argc != 2) {
+		help(argv);
+		return 0;
+	}
 
   cv::namedWindow( "Example 2-3", cv::WINDOW_AUTOSIZE );
 
@@ -30,7 +46,7 @@ int main( int argc, char** argv ) {
 //      cout <<((c&(0x1<<(31-i)))?1:0);
 //    }
 //      cout <<endl;
-//      cout <<"Breakey: '" <<(int)c <<"'"<<endl;
+//      cout <<"Break key: '" <<(int)c <<"'"<<endl;
 //    if( (signed char)c >= 0 ) {
 //      break;
 //    }

example_02-04.cpp

@@ -1,3 +1,6 @@
+//Example 2-4. Adding a trackbar slider to the basic viewer window for moving around
+//within the video file
+
 #include "opencv2/highgui/highgui.hpp"
 #include "opencv2/imgproc/imgproc.hpp"
 #include <iostream>
@@ -18,7 +21,24 @@ void onTrackbarSlide( int pos, void *) {
   g_dontset = 0;
 
 }
+
+
+void help(char** argv ) {
+	std::cout << "\n"
+	<< "2-04: Addeing a trackbar to a basic viewer for moving w/in the video file \n"
+	<< argv[0] <<" <path/video>\n"
+	<< "For example:\n"
+	<< argv[0] << " ../tree.avi\n"
+	<< std::endl;
+}
+
+
 int main( int argc, char** argv ) {
+
+	if (argc != 2) {
+		help(argv);
+		return 0;
+	}
 
   cv::namedWindow( "Example 2-4", cv::WINDOW_AUTOSIZE );
 

example_02-05.cpp

@@ -1,6 +1,25 @@
+// Example 2-5. Loading and then smoothing an image before it is displayed on the screen
+
 #include <opencv2/opencv.hpp>
 
+
+
+void help(char** argv ) {
+	std::cout << "\n"
+	<< "2-05: load and smooth an image before displaying \n"
+	<< argv[0] <<" <path/video>\n"
+	<< "For example:\n"
+	<< argv[0] << " ../tree.avi\n"
+	<< std::endl;
+}
+
+
 int main( int argc, char** argv ) {
+
+	if (argc != 2) {
+		help(argv);
+		return 0;
+	}
 
   // Load an image specified on the command line.
   //

example_02-06.cpp

@@ -1,6 +1,24 @@
+// Example 2-6. Using cv::pyrDown() to create a new image that is half the width and
+// height of the input image
 #include <opencv2/opencv.hpp>
 
+void help(char** argv ) {
+	std::cout << "\n"
+	<< "2-06: AUsing cv::pyrDown() to create a new image that is half the width and"
+    << "      height of the input image\n"
+	<< argv[0] <<" <path/image>\n"
+	<< "For example:\n"
+	<< argv[0] << " ../faces.png\n"
+	<< std::endl;
+}
+
+
 int main( int argc, char** argv ) {
+
+	if (argc != 2) {
+		help(argv);
+		return 0;
+	}
 
   cv::Mat img1,img2;