Implementing binary search in ruby

ruby_binary_search.rb

# recursive implementation of binary search in Ruby

def search(arr, val, start_index, end_index)
  median = (start_index + end_index) / 2
  if(arr[median] == val)
    puts "#{val} is in this list."
  elsif(start_index >= end_index)
    puts "#{val} is not in this list."
  else
    if(val > arr[median])
      search(arr, val, median+1, end_index)
    else
      search(arr, val, start_index, median-1)
    end	
  end
end