text: #!/usr/bin/env python
  ###############################
  # function: login_system
  # author: dhl
  # date:	2019-05-24
  # env: python3
  ###############################
  
  list_data = [3, 7, 2, 5, 20, 11]
  
  def bubble_sort(data):
      for i in range(len(list_data)-1,0,-1):
          count = 0
          for j in range(0,i):
              if list_data[j] > list_data[j+1]:
                  list_data[j],list_data[j+1] = list_data[j+1],list_data[j]
                  count += 1
          if count == 0:
              return
  
  bubble_sort(list_data)
  print(list_data)
  