#!/usr/bin/env ruby
# This code comes from http://ruby-it.org/pages/Iterare+Sequenze
# Check the page for copyright notice and explanations



 >> count=0
 => 0
 >> ary= [1,2,3,4,5,6,7,8]
 => [1, 2, 3, 4, 5, 6, 7, 8]
 >> for i in ary
 >>  print ary[count-1],i,ary[count+1],"\n"
 >>  count+=1
 >> end
 812
 123
 234
 345
 456
 567
 678
 78nil
 => [1, 2, 3, 4, 5, 6, 7, 8]

 >> ary.each_with_index do |el,i|
 ?>  print ary[i-1],el,ary[i+1],"\n"
 >> end
 812
 123
 234
 345
 456
 567
 678
 78nil
 => [1, 2, 3, 4, 5, 6, 7, 8]

 >> require 'enumerator'
 => true
 >> ary.each_cons(3) do |pre,el,suc|
 ?>   print pre,el,suc,"\n"
 >> end
 123
 234
 345
 456
 567
 678
 => nil