class StudentRecord(object):
  """
  Remember, the body of an object must all be indented to the same level, just
  like the body of any other block of Python code
  """

  def __init__(self, name, age, major, gpa):
    """
    Constructor; parameters are initial values for:
      name (string), age (int), major (string), gpa (float)
    """
    # initialize several member variables with parameter values
    self.name = name
    self.age = age
    self.major = major
    self.gpa = gpa
    # initialize an empty list to store student's grades
    self.grades = []

  ##########################
  """
  Getter methods; each returns the value of the appropriate member variable
  """

  def get_name(self):
    """ Getter method for name
      - no parameters beyond 'self'
      - returns value of "name" field
    """
    return self.name

  def get_age(self):
    """ Getter method for age
      - no parameters beyond 'self'
      - returns value of "age" field
    """
    return self.age

  def get_major(self):
    """ Getter method for major
      - no parameters beyond 'self'
      - returns value of "major" field
    """
    return self.major

  def get_gpa(self):
    """ Getter method for gpa
      - no parameters beyond 'self'
      - returns value of "gpa" field
    """
    return self.gpa

  def get_grades(self):
    """ Getter method for grades
      - no parameters beyond 'self'
      - returns value of "grades" field
    """
    return self.grades

  ##########################
  """
  Setter methods; each modifies the value of the appropriate member variable
  """

  def set_name(self, newName):
    """ Setter method for name
      - takes a new value for the 'name' field
      - no return value
    """
    self.name = newName

  def set_major(self, newMajor):
    """ Setter method for major; must be in list of options
      - takes a new value for the 'major' field
      - no return value
    """
    validMajors = ["CS", "Math", "English", "Philosophy"]
    if (newMajor in validMajors):
      self.major = newMajor
    else:
      print("Warning; trying to set invalid major: \"%s\"" % (newMajor))

  def set_age(self, newAge):
    """ Setter method for age
      - takes a new value for the 'age' field
      - no return value
    """
    if (age >= 0):
      self.age = newAge
    else:
      print("Warning; age must not be negative")


  ##########################
  """
  Modifier methods change values of members, but don't directly assign
  new values to them
  """

  def add_grade(self, newGrade):
    """ modifier method for list of grades
      - takes a new grade to add to list
      - no return value
    """
    self.grades.append(newGrade)

  def birthday(self):
    """
    Method to run if it's a student's birthday; print a message and
    increment the student's age.
      No parameters or return value.
    """
    print("Happy birthday, %s!", (self.name))
    self.age = self.age + 1

  def update_gpa(self):
    """
    Method to re-calculate GPA based on list of grades
    No parameters or return value.
    """
    total = 0
    for i in range(len(self.grades)):
      total = total + self.grades[i]

    self.gpa = total / len(self.grades)

  ##########################

  def __str__(self):
    """
    to-string method, returns a string containing info about the student
      No parameters
      returns string
    """
    return "%-12s (age: %d,   major: %s, \tgpa: %.2f)" % \
            (self.name, self.age, self.major, self.gpa)

##########################
# End of class definition
##########################

def main():
  """
  main function for testing the class
  """

  print("Running tests for StudentRecord class...")

  print("Testing constructor...")
  ada = StudentRecord("Ada", 21, "CS", 4.0)
  beth = StudentRecord("Beth", 19, "Math", 3.8)
  cal = StudentRecord("Cal", 20, "English", 3.4)

  slst = [ada, beth, cal]
  print("Testing to-string...")
  for s in slst:
    print(s)

  print("Testing getter methods...")
  print(ada.get_name())
  print(ada.get_age())
  print(ada.get_major())
  print(ada.get_gpa())
  print(ada.get_grades())

  print("testing grade list methods...")
  ada.add_grade(4.0)
  ada.add_grade(4.0)
  ada.add_grade(3.5)
  print("grade list should be: [4.0, 4.0, 3.5]")
  print(ada.get_grades())
  ada.update_gpa()
  print("new gpa should be: 3.83")
  print("%.2f" % ada.get_gpa())



# only run main if Python was run directly on this file (don't run on import)
if (__name__ == "__main__"):
  main()