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.




( ( middle3
  =   x p
    .     @(!arg:? [?p:? [(1/2*!p+-3/2) %?x [(1/2*!p+3/2) ?)
        & !x
      |   !arg
          ( !p:<3&"is too small"
          | "has even number of digits"
          )
  )
&     123 12345 1234567 987654321 10001 -10001 -123 -100 100
      -12345 1 2 -1 -10 2002 -2002 0
  : ?L
& whl'(!L:%?e ?L&out$(middle3$!e))
& 
);
 