text: ''' swapping '''
  
  print('-- swapping using 3rd variable ---')
  a = 10
  b = 20
  print('-- Before swapping -- a: {} b: {}'.format(a, b))
  temp = a
  a = b
  b = temp
  print('-- After swapping -- a: {} b: {}'.format(a, b))
  
  print('--' * 20)
  
  print('-- swapping using 3rd variable ---')
  c = 28
  d = 9
  print('-- Before swapping -- c: {} d: {}'.format(c, d))
  c = c + d
  d = c - d
  c = c - d
  print('-- After swapping -- c: {} d: {}'.format(c, d))
  
  
  