Task

Write a function/procedure/subroutine that is called with an integer value and returns the middle three digits of the integer if possible or a clear indication of an error if this is not possible.

Note: The order of the middle digits should be preserved.

Your function should be tested with the following values; the first line should return valid answers, those of the second line should return clear indications of an error:

123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -12345
1, 2, -1, -10, 2002, -2002, 0

Show your output on this page.




 
(define (middle3 x)
    (if (even? (length x))
        (println "You entered " x ". I need an odd number of digits, not " (length x) ".")
        (if (< (length x) 3)
            (println "You entered " x ". Sorry, but I need 3 or more digits.")
            (println "The middle 3 digits of " x " are " ((- (/ (- (length x) 1) 2) 1) 3 (string (abs x))) ".")
        )
    )
)
 
(map middle3 lst)
 