title: cv.h: file not found opencv
body: <p>I'm running this code: </p>
  
  <pre><code>#include &lt;opencv2/core/core.hpp&gt;
  #include &lt;opencv2/highgui/highgui.hpp&gt;
  #include &lt;iostream&gt;
  
  using namespace cv; 
  using namespace std;
  
  int main( int argc, char** argv ) {
      if( argc != 2)
      {
       cout &lt;&lt;" Usage: display_image ImageToLoadAndDisplay" &lt;&lt; endl;
       return -1;
      }
  
      Mat image;
      image = imread(argv[1], CV_LOAD_IMAGE_COLOR);   // Read the file
  
      if(! image.data )                              // Check for invalid input
      {
          cout &lt;&lt;  "Could not open or find the image" &lt;&lt; std::endl ;
          return -1;
      }
  
      namedWindow( "Display window", CV_WINDOW_AUTOSIZE );// Create a window for display.
      imshow( "Display window", image );                   // Show our image inside it.
  
      waitKey(0);                                          // Wait for a keystroke in the window
      return 0; }
  </code></pre>
  
  <p>But it isn't working for me because it shows this error on my screen when I write cmake . in terminal: </p>
  
  <blockquote>
    <p>cv.h: file not found.</p>
  </blockquote>
  
  <p>Could anyone help me? It was working one month ago.</p>