设计一个学生成绩管理程序，实现按班级完成对学生成绩信息的录入和修改，并用文件保存。实现按班级输出学生的成绩单；实现按学号和姓名进行查询，按平均成绩进行排序功能。用户调试

以下是一个简单的学生成绩管理程序，包含录入学生信息、修改学生信息、保存学生信息、输出学生成绩单、查询学生信息和排序学生信息功能。具体实现细节可以根据需要进行调整。

import os

class Student:
    def __init__(self, name, number, score):
        self.name = name
        self.number = number
        self.score = score
    
    def __str__(self):
        return f"{self.name},{self.number},{self.score}"
    
class Grade:
    def __init__(self, name):
        self.name = name
        self.students = []
        
    def add_student(self, student):
        self.students.append(student)
    
    def find_student_by_number(self, number):
        for student in self.students:
            if student.number == number:
                return student
        return None
    
    def find_student_by_name(self, name):
        for student in self.students:
            if student.name == name:
                return student
        return None
    
    def sort_students_by_score(self):
        self.students = sorted(self.students, key=lambda x: x.score, reverse=True)
    
    def __str__(self):
        return f"{self.name}班级"
        
class GradeManager:
    def __init__(self):
        self.grades = []
        
    def add_grade(self, grade):
        self.grades.append(grade)
    
    def find_grade_by_name(self, name):
        for grade in self.grades:
            if grade.name == name:
                return grade
        return None
    
    def save_grades(self, filename):
        with open(filename, "w") as f:
            for grade in self.grades:
                for student in grade.students:
                    f.write(f"{grade.name},{str(student)}\n")
    
    def load_grades(self, filename):
        with open(filename, "r") as f:
            lines = f.readlines()
            for line in lines:
                parts = line.strip().split(",")
                grade_name = parts[0]
                student_name = parts[1]
                student_number = parts[2]
                student_score = int(parts[3])
                grade = self.find_grade_by_name(grade_name)
                if grade is None:
                    grade = Grade(grade_name)
                    self.add_grade(grade)
                student = Student(student_name, student_number, student_score)
                grade.add_student(student)
                
    def print_grade(self, grade_name):
        grade = self.find_grade_by_name(grade_name)
        if grade is None:
            print(f"没有找到{grade_name}班级")
            return
        print(f"{grade}学生成绩单：")
        for student in grade.students:
            print(f"{student.name}\t{student.number}\t{student.score}")
    
    def query_student_by_number(self, number):
        for grade in self.grades:
            student = grade.find_student_by_number(number)
            if student is not None:
                print(f"{grade}：{student.name}\t{student.number}\t{student.score}")
                return
        print(f"没有找到学号为{number}的学生")
    
    def query_student_by_name(self, name):
        for grade in self.grades:
            student = grade.find_student_by_name(name)
            if student is not None:
                print(f"{grade}：{student.name}\t{student.number}\t{student.score}")
                return
        print(f"没有找到姓名为{name}的学生")
        
    def sort_students_by_score(self):
        for grade in self.grades:
            grade.sort_students_by_score()
        
if __name__ == "__main__":
    manager = GradeManager()
    filename = "grades.txt"
    if os.path.exists(filename):
        manager.load_grades(filename)
    while True:
        print("欢迎使用学生成绩管理程序！")
        print("1. 录入学生成绩")
        print("2. 修改学生成绩")
        print("3. 输出学生成绩单")
        print("4. 查询学生信息")
        print("5. 排序学生成绩")
        print("6. 保存学生成绩")
        print("0. 退出程序")
        choice = input("请选择操作：")
        if choice == "1":
            name = input("请输入班级名称：")
            grade = manager.find_grade_by_name(name)
            if grade is None:
                grade = Grade(name)
                manager.add_grade(grade)
            number = input("请输入学号：")
            student = grade.find_student_by_number(number)
            if student is not None:
                print("该学号已存在，请重新输入！")
                continue
            name = input("请输入姓名：")
            score = input("请输入成绩：")
            student = Student(name, number, int(score))
            grade.add_student(student)
            print("学生成绩录入成功！")
        elif choice == "2":
            number = input("请输入学号：")
            student = None
            for grade in manager.grades:
                student = grade.find_student_by_number(number)
                if student is not None:
                    break
            if student is None:
                print("没有找到该学号的学生！")
                continue
            name = input("请输入姓名：")
            score = input("请输入成绩：")
            student.name = name
            student.score = int(score)
            print("学生成绩修改成功！")
        elif choice == "3":
            name = input("请输入班级名称：")
            manager.print_grade(name)
        elif choice == "4":
            method = input("请选择查询方式（1. 按学号查询，2. 按姓名查询）：")
            if method == "1":
                number = input("请输入学号：")
                manager.query_student_by_number(number)
            elif method == "2":
                name = input("请输入姓名：")
                manager.query_student_by_name(name)
            else:
                print("请输入正确的选项！")
        elif choice == "5":
            manager.sort_students_by_score()
            print("学生成绩已按平均成绩排序！")
        elif choice == "6":
            manager.save_grades(filename)
            print("学生成绩已保存！")
        elif choice == "0":
            break
        else:
            print("请输入正确的选项！")

用户可以根据提示进行操作，程序将会根据用户的输入进行相应的操作。程序将学生成绩保存在名为“grades.txt”的文件中，用户可以多次运行程序来读取和修改该文件中的数据。