title: error: QApplication: No such file or directory?
body: <p>I've been following someone's Youtube playlist of tutorials for Qt.  When I try to follow the <a href="http://www.youtube.com/watch?v=Gk3zh5lA4ww" rel="nofollow">Basic Application and HTML Aware Widgets</a>, I am getting this error when trying create an empty Qt project with an added c++ class:</p>
  
  <pre><code>error: QApplication: No such file or directory
  </code></pre>
  
  <p>I have the latest Qt creator and library installed and its underlining the #includes...</p>
  
  <pre><code>#include &lt;QApplication&gt;
  #include &lt;QLabel&gt;
  
  int main(int argc, char * argv[])
  {
      QApplication app(argc, argv);
      QLabel *label = new QLabel("hello world");
  
      label.show();
  
      return app.exec();
  }
  </code></pre>
  
  <p>to answer below: I tried that, my .pro looks like this:</p>
  
  <p>QT      += core widgets
  SOURCES += main.cpp</p>
  
  <p>and I got these errors..</p>
  
  <pre><code>In function 'int qMain(int, char**)':
  error: request for member 'show' in 'label', which is of pointer type 'QLabel*' (maybe you meant to use '-&gt;' ?)
  </code></pre>