Re: how to organize several class and their instance in windows programming

"asm23" <asmwarrior@gmail.com> ha scritto nel messaggio
news:g15gls$tdm$1@aioe.org...


[...]


You may consider defining a class that stores instances of those "shared"
"component" classes, e.g.

 // Stores all the subsystems of your app
 // (image processing, motion control, ...)
 class CSystemCore
 {
 public:
   CImageProc m_image;
   CMotionControl m_motor;
   CNetwork m_socket;
    ...

   //
   // Of course you may declare the above instances
   // as private/protected, and just expose some
   // public methods for accessing them, e.g.
   //
   // private:
   // CImageProc m_image;
   //
   // public:
   // CImageProc & GetImageProc() { return m_image; }
   //
 };

Then, you can pass a pointer to the CSystemCore instance to each of the
"component" classes (like CImageProc, etc.), e.g.

  // Forward reference
  class CSystemCore;

  CImageProc
  {
     ...
     // Needs to access to all system components
     CSystemCore * m_pSystem;
  };

So, inside your CImageProc methods, you can reference the other system
components (like CMotionControl), using the pointer to CSystemCore, e.g.

  void CImageProc::DoSomething()
  {
     ...

     // Need to control the m_motor CMotionControl instance
     m_pSystem->m_motor.DoSomethingWithMotor(...);

     // or more elegant (with private instance of CMotionControl
     // and public accessor):
     // m_pSystem.GetMotionControl().DoSomethingWithMotore(...);
  }

Of course, when you create the CSystemCore instance, you must set the
pointer to it into several component classes, e.g.

  // In CSystemCore constructor
  CSystemCore::CSystemCore()
  {
      m_image.m_pSystem = this;
      m_motor.m_pSystem = this;
  }

Or you can define proper constructors for CImageProc, CMotionContorl, etc.

  CImageProc( SystemCore * pSystem )
     : m_pSystem( pSystem )
    ...
  {
     ...
  }

  CMotionControl( SystemCore * pSystem )
    : m_pSystem( pSystem )
    ...
  {
     ...
  }

And initialize these instances in CSystemCore constructor like this:

  CSystemCore::CSystemCore()
     : m_image( this ),
       m_motor( this ),
      ...
  {
     ...
  }

So, you can make CSystemCore a singleton in your app, or you can put it into
your CDocument class, or in whatever place your design suggests.

HTH,
Giovanni