#!/usr/bin/perl -w
#
#  Sort version numbers

use strict;
use warnings;

{
    my @versions = qw/2.4.74 3.2.5 1.14.56 1.45.2 3.14.75/;

    print "Original version string:\n" . join( "\n", @versions ) . "\n";
    print "Sorted version strings:\n"
      . join( "\n", sort compareVersionStrings @versions ) . "\n";
}

#  Compare two version strings.
#
#  Among other assumptions, this code assumes that the version strings have the
#  same number of elements in them. Thus, comparing 3 against 2 will work; as
#  will 3.1 against 2.7 and 3.1.4 against 2.7.18. Comparing 2.0 against 4 will
#  fail, as will 2.0 against 4.5.6.

sub compareVersionStrings {

    my ( @a, @b );

    my @left  = split( /\./, $a );
    my @right = split( /\./, $b );

    return ( $left[0] <=> $right[0]
          || $left[1] <=> $right[1]
          || $left[2] <=> $right[2] );
}