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.




procedure main(a)
   every n := !a do write(right(n,15)," -> ",midM(n))
end
 
procedure midM(n,m)
   /m := 3
   n := abs(n)
   return n ? if (*n >= m) then
                 if (((*n-m) % 2) = 0) then (move((*n - m)/2),move(m))
                 else "wrong number of digits"
              else "too short"
end