Why is caddr[(A B C)] = C?

Question

Ideally in LISP:

caddr[(A B C)] = car[cdr[cdr[(A B C)]]] = car[cdr[(B C)]] = car[C] = Undefined.

But the book says answer is C. Can anyone please explain?

Thanks a lot.

Answer 1

Your mistake is that cdr[(B C)] is the list (C), not the atom C.

Then car[(C)] is C.

Answer 2

(cdr '(b c)) is the list (c), not the atom c, so the expression becomes (car '(c)) not (car c)

? (cdr '(b c))
(C)

? (car '(c))
C