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Middle three digits: Difference between revisions
Added Racket version
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Line 794:
>>> </lang>
=={{header|Python}}==
<lang racket>
#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))
</lang>
The output:
<lang racket>
'("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")
</lang>
=={{header|REXX}}==
<lang rexx>/* REXX ***************************************************************
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