A-M baby
This commit is contained in:
parent
764da6cbbb
commit
db842d013d
19005 changed files with 197040 additions and 7 deletions
14
Task/Middle-three-digits/Racket/middle-three-digits-1.rkt
Normal file
14
Task/Middle-three-digits/Racket/middle-three-digits-1.rkt
Normal file
|
|
@ -0,0 +1,14 @@
|
|||
#lang racket
|
||||
(define (middle x)
|
||||
(cond
|
||||
[(negative? x) (middle (- x))]
|
||||
[(< x 100) "error: number too small"]
|
||||
[else
|
||||
(define s (number->string x))
|
||||
(define l (string-length s))
|
||||
(cond [(even? l) "error: number has even length"]
|
||||
[else (define i (quotient l 2))
|
||||
(substring s (- i 1) (+ i 2))])]))
|
||||
|
||||
(map middle (list 123 12345 1234567 987654321 10001 -10001 -123 -100 100 -12345))
|
||||
(map middle (list 1 2 -1 -10 2002 -2002 0))
|
||||
|
|
@ -0,0 +1,3 @@
|
|||
'("123" "234" "345" "654" "000" "000" "123" "100" "100" "234")
|
||||
'("error: number too small" "error: number too small" "error: number too small" "error: number too small"
|
||||
"error: number has even length" "error: number has even length" "error: number too small")
|
||||
Loading…
Add table
Add a link
Reference in a new issue