def div(dividend=1.0, divisor=1.0):
  r = dividend / divisor
  print "Result = ", r

def set(vec, element, pos=0, up=True):
  if up:
    vec[pos] = element
  else:
    vec[-pos] = element

def swap(a, b):
  print "Before: ", a, b
  aux = a
  a = b
  b = aux
  print "After: ", a, b