#!/bin/perl

=pod

Perl Weekly Challenge - 135
 - https://perlweeklychallenge.org/blog/perl-weekly-challenge-135/#TASK1

Author: Niels 'PerlBoy' van Dijke

TASK #1 › Middle 3-digits
Submitted by: Mohammad S Anwar

You are given an integer.

Write a script find out the middle 3-digits of the given integer, if possible otherwise throw sensible error.

=cut

use v5.16;
use strict;
use warnings;

use Test::More;

# Prototype(s)
sub middle3numbers($);

is middle3numbers(1234567),345;
is middle3numbers(1020304050607),'040';
is middle3numbers(-123),123;
is middle3numbers(1),'too short';
is middle3numbers(1010),'even number of digits';
is middle3numbers('Perl5'),'not an integer number';

done_testing;


sub middle3numbers($) {
  my $n = $_[0];

  return 'not an integer number'  if  $n !~ m#^[-]?\d+$#;

  $n = abs($n);
  my $l = length($n);
  return 'too short' if $l < 3;
  return 'even number of digits' if $l % 2 == 0;
  return substr($n,int($l/2)-1,3);
}