python： 设计一个程序，运行时输入班级人数，根据人数输入这个班级学生的成绩，输出学生成绩，计算总分和平均分。再将低于平均分的人数统计出来，并对学生成绩进行从高到低排序。

在Python中，你可以设计一个简单的命令行程序来满足这些需求。首先，我们需要定义一个`Student`类来存储姓名和成绩，然后创建一个函数来获取输入并处理数据。下面是一个示例：

class Student:
    def __init__(self, name, score):
        self.name = name
        self.score = score

def get_student_data(num_students):
    students = []
    for i in range(num_students):
        name = input(f"请输入第{i+1}名学生的姓名：")
        score = float(input(f"请输入第{i+1}名学生的分数："))
        students.append(Student(name, score))
    return students

def calculate_average(students):
    total_score = sum(student.score for student in students)
    average_score = total_score / len(students)
    return total_score, average_score

def filter_below_average(students, average_score):
    below_average = [student for student in students if student.score < average_score]
    return below_average

def sort_scores(students):
    sorted_students = sorted(students, key=lambda s: s.score, reverse=True)
    return sorted_students

def main():
    num_students = int(input("请输入班级人数："))
    students = get_student_data(num_students)

    total_score, average_score = calculate_average(students)
    print(f"总分：{total_score}, 平均分：{average_score}")

    below_average_count = len(filter_below_average(students, average_score))
    print(f"低于平均分的学生有 {below_average_count} 人")

    print("学生成绩从高到低排序：")
    for student in sort_scores(students):
        print(f"{student.name}: {student.score}")

if __name__ == "__main__":
    main()

当你运行此程序时，它会提示你依次输入每个学生的姓名和分数，最后显示总分、平均分，以及低于平均分的学生数量和学生成绩的排序结果。