simple question on Class-Members

[jacek]

now I don't know.

So maybe you should redesign your classes?

For example like this:

void DOOR::draw( const QImage& img ) 
{
   // ...
}
 
void build::draw()
{
   // ...
   for( std::vector<DOOR>::iterator it = door.begin(); it != door.end(); ++it ) {
      it->draw( imm );
   }
   // ...
}

void DOOR::draw( const QImage& img ) 
{
   // ...
}

void build::draw()
{
   // ...
   for( std::vector<DOOR>::iterator it = door.begin(); it != door.end(); ++it ) {
      it->draw( imm );
   }
   // ...
}

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Other possibility is that each of DOOR instances would hold a pointer or reference to a build instance:

void DOOR::draw() 
{
   // ...
   QImage img( _build->image() );
   // ...
}
 
const QImage& build::image() const 
{
   return _imm;
}

void DOOR::draw() 
{
   // ...
   QImage img( _build->image() );
   // ...
}

const QImage& build::image() const 
{
   return _imm;
}

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Everything depends on the way you want to use those two classes and on things what they represent.