python
class Student:
def __init__(self, name, score):
self.name = name
self.score = score
class StudentIterator:
def __init__(self, students):
self.students = students
self.current = 0
def __next__(self):
if self.current >= len(self.students):
raise StopIteration
else:
student = self.students[self.current]
self.current += 1
return student
def __iter__(self):
return self
class StudentCollection:
def __init__(self):
self.students = []
def add_student(self, student):
self.students.append(student)
def __iter__(self):
return StudentIterator(self.students)
def calculate_average_score(student_collection):
total_score = 0
count = 0
for student in student_collection:
total_score += student.score
count += 1
return total_score / count
collection = StudentCollection()
average_score = calculate_average_score(collection)
