07/06/20 21:24:07
(define (remove-at! ls n)
(if (null? ls)
(error "list too short")
(if (zero? n)
((lambda (tmp)
(set-car! ls (cadr ls))
(set-cdr! ls (cddr ls))
tmp)
(car ls))
(remove-at! (cdr ls) (- n 1)))))
07/06/20 21:24:07
(define (remove-at! ls n)
(if (null? ls)
(error "list too short")
(if (zero? n)
((lambda (tmp)
(set-car! ls (cadr ls))
(set-cdr! ls (cddr ls))
tmp)
(car ls))
(remove-at! (cdr ls) (- n 1)))))