(define (list-cruncher base proc combiner lst)
(if (null? lst)
base
(combiner (proc (car lst))
(list-cruncher base proc combiner
(cdr lst)))))
(define (sumlist p)
(list-cruncher _____ ___________________ _____ p))
(define (map f p)
(list-cruncher _______ ______ ______ p))
(define (length p)
(list-cruncher ______ _____________ + p))
Why would it be impossible to correctly define list? using just list-cruncher?
Define find-closest-number, a procedure that takes two
parameters, a goal and a list of numbers, and produces the number in the
list numbers list that is closest to goal.
(define (find-closest-number goal numbers)
(if (= 1 (length numbers))
(car numbers)
(if (< (abs (- goal (car numbers)))
(abs (- goal
(find-closest goal (cdr numbers)))))
(car numbers)
(find-closest goal (cdr numbers)))))
(define (find-closest goal lst closeness)
(if (= 1 (length lst))
(car lst)
(if (< (closeness goal (car lst))
(closeness goal
(find-closest goal (cdr lst) closeness)))
(car lst)
(find-closest goal (cdr lst) closeness))))
(define (pick-closest closeness goal num1 num2)
(if (< (closeness goal num1)
(closeness goal num2))
num1
num2))
(define (find-closest goal lst closeness)
(if (= 1 (length lst))
(car lst)
(pick-closest closeness goal (car lst)
(find-closest goal (cdr lst) closeness))))
What is the difference between RTN and BNF?
Song ::= Verse VBBD VBBD Better CodaChallenge Problem
VBBD ::= Verse Bridge Bridge Dadada (ends on C)
Coda ::= F Eb Bb F Coda
Note: the Coda has no base case, and should continue forever (time permitting).