Quick Sort Module For Array

quick_sort.rb

module QuickSort
  
  module InstanceMethods
    
      def swap(arr, a, b)
         arr[a], arr[b] = arr[b], arr[a]
      end

      def partition(arr, left, right)
      
        pivot = ((left + right) / 2).floor
  
        while left <= right do
        
          while arr[left] < arr[pivot] do
            left = left + 1
          end
    
          while arr[right] > arr[pivot] do
            right = right - 1
          end
    
          if left <= right
            swap(arr, left, right)
            left = left + 1
            right = right - 1
          end
        
        end
      
        left
      end
    
      def quicksort!(arr = [], left = 0, right = self.count - 1)

        if arr == []
          arr = self
        end
  
        pivot = partition(arr, left, right)

        if left < pivot - 1
          quicksort!(arr, left, pivot - 1)
        end
  
        if right > pivot
          quicksort!(arr, pivot, right)
        end

        arr
    end
  
    def quicksort(arr = [], left = 0, right = self.count - 1)
      if arr == []
        arr = self.clone
      end

      pivot = partition(arr, left, right)

      if left < pivot - 1
        quicksort(arr, left, pivot - 1)
      end

      if right > pivot
        quicksort(arr, pivot, right)
      end

      arr
    end
  
  end  
  
  def self.included(receiver)
    receiver.send :include, InstanceMethods
  end
  
end

class Array
  include QuickSort
end

Returning a sorted result:

example = [213,3,6,7,8,2,5,7,8.3,7]
result = example.quicksort
puts result
puts example

Output

[2, 3, 5, 6, 7, 7, 7, 8, 8.3, 213]
[213,3,6,7,8,2,5,7,8.3,7]

Or just sort the array itself

example.quicksort!
puts example

Output

[2, 3, 5, 6, 7, 7, 7, 8, 8.3, 213]