C / C++ / MFC

<br />
Graphics *graphics = NULL; // Global declaration<br />
<br />
...<br />
<br />
graphics = new Graphics(TheHDC); // initialization<br />
<br />
...<br />
<br />
void Draw(int x, int y, int x2, int y2)<br />
{<br />
Pen blackPen(Color(255, 0, 0, 0), 2);<br />
graphics->DrawLine(&blackPen, x, y, x2, y2);<br />
}<br />

<br />
#include "stdafx.h"<br />
#include <assert.h><br />
<br />
/* Compile options needed: none<br />
   */ <br />
<br />
   class A;<br />
<br />
   void fcn( A* );<br />
<br />
   class A<br />
   {<br />
   public:<br />
       virtual void f() = 0;<br />
       A() { fcn( this ); }<br />
   };<br />
<br />
   class B : A<br />
   {<br />
       void f() { }<br />
   };<br />
<br />
   void fcn( A* p )<br />
   {<br />
       p->f();<br />
   }<br />
<br />
   // The declaration below invokes class B's constructor, which<br />
   // first calls class A's constructor, which calls fcn. Then<br />
   // fcn calls A::f, which is a pure virtual function, and<br />
   // this causes the run-time error. B has not been constructed<br />
   // at this point, so the B::f cannot be called. You would not<br />
   // want it to be called because it could depend on something<br />
   // in B that has not been initialized yet.<br />
<br />
int APIENTRY WinMain(HINSTANCE hInstance,<br />
                     HINSTANCE hPrevInstance,<br />
                     LPSTR     lpCmdLine,<br />
                     int       nCmdShow)<br />
{<br />
 	// TODO: Place code here.<br />
    __try {<br />
   B b;<br />
    }<br />
   __except(EXCEPTION_EXECUTE_HANDLER) {<br />
       assert (false);<br />
   }<br />
<br />
	return 0;<br />
}<br />
<br />