Write a lisp function that counts number of atoms in a list?

Answer 1

1. Count the number of atoms in a list.

A. (defun only-atoms (listx)

(cond ((null listx) t)

((atom listx) 2)

((atom (first listx)) (only-atoms (rest listx)))

(nil (+ 1 (only-atoms (first listx))

(only-atoms (rest listx))))))

Answer 2

Ans.

COUNT-ATOMS

Define function that counts the atoms in a list (at all levels)

> (defun count-atoms(L)

(cond ((null l) 0)

((atom l) 1)

(t (+ (count-atoms (car l))

(count-atoms (cdr l))))))

COUNT-ATOMS

> (count-atoms '(a b c))

3

> (count-atoms '(a (b c)))

3

> (count-atoms '(((a))))

1

Answer 3

Here is a Lisp function that counts the number of atoms in a list:

(defun count-atoms (lst)
  (cond
    ((null lst) 0)
    ((atom lst) 1)
    (t (+ (count-atoms (car lst)) (count-atoms (cdr lst))))
  )
)

This function recursively traverses the list and counts each atom encountered. It returns the total count of atoms in the list.