C / C++ / MFC

tom groezer wrote:

Why is a reference then returned in case of assigment operator where a dereferenced pointer is returned?

class A
{
   int integer;
 
public:
   A()  {integer = 0;}
 
   int GetInt()  {return integer;}
 
   A &operator=( A &a )
   {
      integer = a.integer;
      return *this;
   }
  
   int operator=( int i )
   {
      integer = i;
      return i;
   }
};

class B
{
   double dbl;
 
public:
   B()  {dbl = 0.0;}
 
   B &operator=( double newdbl )
   {
      dbl = newdbl;
      return *this;
   }
 
   B *operator=( B *b )
   {
      dbl = b->dbl;
      return this;
   }
 
   B &operator=( A &a )
   {
      dbl = (double)a.GetInt();
      return *this;
   }
};
...
A a1;
A a2;
B b1;
B b2;
 
a2 = 3;           // a2 == 3
a1 = a2;          // a1 == 3
int i = a1 = 4;   // a1 == 4, i == 4 
 
b1 = 1.25;
b2 = 2.50;
B* bp = b1 = &b2; // b1 == 2.50, bp == &b1
b2 = a1;          // b2 == 4.0

tom groezer wrote:

Will it be correct if I retruned the same way from other functions of a class or is it that we could this only in assignment and copy constructor.

tom groezer wrote:

0xFFFF

Mark Salsbery wrote:

language definition does NOT require a long to be 32 bits.

T* p = NULL;
if (p != NULL)
{
    delete p;
    p = NULL;
}

// Add to CMainFrame class
afx_msg void OnUpdateDbconnect(CCmdUI* pCmdUI);
...
// Add to CMainFrame's message map 
BEGIN_MESSAGE_MAP(CMainFrame, CFrameWnd)
   ON_UPDATE_COMMAND_UI(ID_ADD_CUSTOMER, OnUpdateAddCustomer)
END_MESSAGE_MAP()
...
// Add the handler method
void CMainFrame::OnUpdateAddCustomer(CCmdUI* pCmdUI) 
{
   if (...some condition...)
      pCmdUI->Enable(FALSE); // disable
   else
      pCmdUI->Enable(TRUE);  // enable
}