#lang racket

(define (my-length xs)
  (define (iterate xs len)
    (if (null? xs)
        len
        (iterate (cdr xs) (+ 1 len))))
  (iterate xs 0))


(define (my-length xs)
  (let iterate ([xs xs] [len 0])
    (if (null? xs)
        len
        (iterate (cdr xs) (+ 1 len)))))