Edit: I was wrong - see cygx's reply --- I'm a bit rusty on the C spec, but I think the author is wrong about #4. The answer refers to an exception for a poi

Edit: I was wrong - see cygx's reply --- I'm a bit rusty on the C spec, but I think the author is wrong about #4. The answer refers to an exception for a pointer that points one past the end of an array. And &a[5] would be valid based on that rule, because it points one past the end of the array a. However (&a + 1) is not valid. It does not point one past the end of an array (because although a is an array, it is not an element of an array.) Having said that I would be surprised if any compiler gave a result other than "2 5". Still, it's technically undefined.