function middleThreeDigits(n)
	if n < 0 then n = -n
	if n < 100 then return ""  ## error code
	if n < 1000 then return string(n)
	if n < 10000 then return ""
	ns = string(n)
	if length(ns) mod 2 = 0 then return ""  ## need to have an odd number of digits for there to be 3 middle
	return mid(ns, length(ns) \ 2, 3)
end function

dim a = {123, 12345, 1234567, 987654321, 10001, -10001, -123, -100, 100, -123451, 2, -1, -10, 2002, -2002, 0}

print "The 3 middle digits of the following numbers are : "
print
for i = 0 to 15
	result = middleThreeDigits(a[i])
	print a[i]; chr(9); " => ";
	if result <> "" then
		print result
	else
		print "Error: does not have 3 middle digits"
	end if
next