title: Namespace with multiple files
body: <p>Inside FileThree.h</p>
  
  <pre><code>#ifndef FILETHREE
  #define FILETHREE
  namespace blue{}
  class Filethree
  {
  public:
      Filethree(void);
      ~Filethree(void);
  };
  #endif
  </code></pre>
  
  <p>Inside FileThree.cpp</p>
  
  <pre><code>#include "Filethree.h"
  #include&lt;iostream&gt;
  using namespace std ;
  namespace blue{
       void blueprint(int nVar){
           cout&lt;&lt;"red::"&lt;&lt;nVar&lt;&lt;endl;
       }
  }
  Filethree::Filethree(void)
  {
  }
  
  Filethree::~Filethree(void)
  {
  }
  </code></pre>
  
  <p>Inside FileFour.h</p>
  
  <pre><code>#ifndef FILEFOUR
  #define FILEFOUR
  namespace red{}
  class FileFour
  {
  public:
      FileFour(void);
      ~FileFour(void);
  };
  #endif
  </code></pre>
  
  <p>Inside FileFour.cpp</p>
  
  <pre><code>#include "FileFour.h"
  #include&lt;iostream&gt;
  using namespace std; 
   namespace red{
       void redprint(double nVar){
           cout&lt;&lt;"red::"&lt;&lt;nVar&lt;&lt;endl;
       }
  }
  FileFour::FileFour(void)
  {
  }
  
  FileFour::~FileFour(void)
  {
  }
  </code></pre>
  
  <p>Inside main.cpp</p>
  
  <pre><code>#include "FileFour.h"
   #include "Filethree.h"
  using namespace red ;
  using namespace blue ;
  
  int main()
  {
      blueprint(12);
  return 0;
  }
  </code></pre>
  
  <p>When i compile the above file it gives me the following error .</p>
  
  <pre><code> error C3861: 'blueprint': identifier not found
  </code></pre>
  
  <p>Can anyone tell me why i am getting this error ?</p>