"""
This is problem 8.11 on page 263 of Zelle's 'Python Programming...' text, namely :

 Write a program that accepts (from a file) a series of daily temps
 and computes degree-days :
   heating: number of degrees over 80
   cooling: number of degress under 60
 and outputs the two totals after all the data has been processed.

See the "run" file that executes this.

Jim M on Oct 13 2008

"""

def get_data(filename):
  """Return a list of data from a file with numbers separated by spaces or newlines."""
  data = []
  try:
    infile = open(filename, 'r')
  except:
    print "Problem opening file."
    return data
  while True:
    line = infile.readline()
    if not line:
      return data
    number_strings = line.split()
    for number_string in number_strings:
      data.append(eval(number_string))
  
def user_filename():
  """Prompt user for a filename."""
  return raw_input("What is the filename? ")

def heating_degreedays(data):
  """Return total of degrees over 80 from a list of degrees on consecutive days."""
  heating  = 0
  hot_temp = 80
  # print " heating ... "  # debug
  for degree in data:
    # print "   " + str(degree)  # debug
    if degree > hot_temp:
      heating = heating + (degree - hot_temp)
  return heating

def cooling_degreedays(data):
  """Return total of degrees over 80 from a list of degrees on consecutive days."""
  cooling  = 0
  cold_temp = 60
  for degree in data:
    if degree < cold_temp:
      cooling = cooling + (cold_temp - degree)
  return cooling

def main():
  print "problem 8.11 on page 263"
  print
  data = get_data(user_filename())
  # print "data = " + str(data)  # debug
  print "Heating degree-days = %i" % heating_degreedays(data)
  print "Cooling degree-days = %i" % cooling_degreedays(data)

main()