C / C++ / MFC

// we have some class called c

int main()
{
  c myObject;
  myObject.a();  // the this pointer in a() below will be &myObject
  c *myPointer = new c;
  myPointer->a(); // the this pointer in a() below will point to the same object as myPointer
  c *myNullPointer = 0;
  myNullPointer->a(); // the this pointer in a() below is null, so accessing i through it will result in an access violation.
}

void c::a()
{
  // these two lines are equivalent.  When referring to a member variable in a
  // member function, there is an implicit "this->" before it.
  this->i = 1;
  i = 1;
}