TITLE: Pointers, arrays, and problems

PROBLEM: C++ has a very large hole concerning type safety regarding pointers
and arrays.


RESPONSE: Taken from class notes on Adv C++ by Desmond Dsouza

class A {
public:
	int av;
};

class B : public A {
public:
	int bv;
};

void f (A* x) 
{
	x[1].av = 0;
}

main ()
{
	B y [100];
	y [0].bv = 1;	

	f (y);

	// One of the B in the array has just been stomped on.
	// This assertion will fail.

	assert (y [0].bv == 1);
}


Never write methods that accept (manipulate) arrays of objects of types
that may be subclasses. Someday they will fail!