str_cc_bm_2.rb

require 'benchmark'
Benchmark.bm(20) do |x|
  x.report ('<<') do
    out = ""
    100_000.times do
      one = 'one'
      two = 'two'
      three = 'three'
      out << "#{one}" << "#{two}" << "#{three}"
    end
  end
  x.report ('concat') do
    out = ""
    100_000.times do
      one = 'one'
      two = 'two'
      three = 'three'
      out.concat(one.concat(two).concat(three))
    end
  end
 x.report('+') do
    out = ""
    100_000.times do
      one = 'one'
      two = 'two'
      three = 'three'
      out += one + two + three
    end
  end
end