Order of n O(n) Example

big-o-benchmark-o(n).rb

require 'benchmark'

def benchmark
  time_in_seconds = Benchmark.realtime { yield }
  time_in_milliseconds(time_in_seconds)
end

def time_in_milliseconds(time_in_seconds)
  (time_in_seconds * 1000).round(2).to_s + ' ms'
end

def copy_string(string, number_of_times)
  string * number_of_times
end

puts benchmark { copy_string('hello world', 1_000_000) }
puts benchmark { copy_string('hello world', 10_000_000) }
puts benchmark { copy_string('hello world', 100_000_000) }

# Here's an example of the output
# > ruby test.rb
# 4.45 ms
# 48.19 ms
# 486.35 ms