一个综合的学生成绩管理系统，要求能够管理若干个学生若干门课程成绩，需要实现以下功能：读取以数据文件（如图 3-1：student.txt）形式存储的学生信息（若没有数据文件则需创建新的数据文件）：能浏览查看学生信息；能添加学生信息：能够修改和删除学生的基本信息：能计算每个学生的总分并进行排名：能统计每门课的最高分、最低分和平均分：能按照学号、姓名、名次等方式 查询学生信息：对学生信息的修改最终都能保存到数据文件中去

基于您提供的需求，一个简单的学生成绩管理系统大致可以分为以下模块：

1. 数据文件读写模块：负责读取和保存学生信息到数据文件中。

2. 学生信息管理模块：可以浏览、添加、修改和删除学生的基本信息。

3. 成绩计算和排名模块：计算每个学生的总分并进行排名，以及统计每门课的最高分、最低分和平均分。

4. 学生信息查询模块：可以按照学号、姓名、名次等方式查询学生信息。

下面是一个简单的Python实现示例，用于参考：

import os

# 定义学生信息类
class Student:
    def __init__(self, id, name, sex, age):
        self.id = id
        self.name = name
        self.sex = sex
        self.age = age
        self.scores = {}

    def add_score(self, course, score):
        self.scores[course] = score

    def get_total_score(self):
        return sum(self.scores.values())

    def __str__(self):
        return f'{self.id}\t{self.name}\t{self.sex}\t{self.age}\t{self.get_total_score():.2f}'

# 数据文件读写模块
class DataManager:
    def __init__(self, filename):
        self.filename = filename

    def read_data(self):
        if not os.path.exists(self.filename):
            with open(self.filename, 'w') as f:
                pass

        students = []
        with open(self.filename, 'r') as f:
            for line in f:
                data = line.strip().split('\t')
                id, name, sex, age = data[:4]
                student = Student(id, name, sex, age)
                scores = data[4:]
                for i in range(0, len(scores), 2):
                    course, score = scores[i], float(scores[i+1])
                    student.add_score(course, score)
                students.append(student)
        return students

    def save_data(self, students):
        with open(self.filename, 'w') as f:
            for student in students:
                scores = [course + '\t' + str(score) for course, score in student.scores.items()]
                line = '\t'.join([student.id, student.name, student.sex, student.age] + scores) + '\n'
                f.write(line)

# 学生信息管理模块
class StudentManager:
    def __init__(self, students):
        self.students = students

    def add_student(self, id, name, sex, age):
        student = Student(id, name, sex, age)
        self.students.append(student)

    def modify_student(self, id, name, sex, age):
        for student in self.students:
            if student.id == id:
                student.name = name
                student.sex = sex
                student.age = age

    def delete_student(self, id):
        for student in self.students:
            if student.id == id:
                self.students.remove(student)

    def __str__(self):
        return '\n'.join([str(student) for student in self.students])

# 成绩计算和排名模块
class ScoreManager:
    def __init__(self, students):
        self.students = students
        self.course_scores = {}

    def calc_course_scores(self):
        for student in self.students:
            for course, score in student.scores.items():
                if course not in self.course_scores:
                    self.course_scores[course] = []
                self.course_scores[course].append(score)

    def get_course_stats(self, course):
        scores = self.course_scores[course]
        return max(scores), min(scores), sum(scores) / len(scores)

    def calc_student_ranks(self):
        total_scores = [student.get_total_score() for student in self.students]
        ranks = [sorted(total_scores, reverse=True).index(score) + 1 for score in total_scores]
        for student, rank in zip(self.students, ranks):
            student.rank = rank

    def __str__(self):
        lines = []
        for course in self.course_scores:
            max_score, min_score, avg_score = self.get_course_stats(course)
            lines.append(f'{course}: max={max_score:.2f}, min={min_score:.2f}, avg={avg_score:.2f}')
        return '\n'.join(lines)

# 学生信息查询模块
class QueryManager:
    def __init__(self, students):
        self.students = students

    def query_by_id(self, id):
        for student in self.students:
            if student.id == id:
                return student
        return None

    def query_by_name(self, name):
        result = []
        for student in self.students:
            if student.name == name:
                result.append(student)
        return result

    def query_by_rank(self, rank):
        result = []
        for student in self.students:
            if student.rank == rank:
                result.append(student)
        return result

# 主程序
def main():
    # 初始化
    data_manager = DataManager('student.txt')
    students = data_manager.read_data()
    student_manager = StudentManager(students)
    score_manager = ScoreManager(students)
    query_manager = QueryManager(students)

    # 计算每门课的最高分、最低分和平均分
    score_manager.calc_course_scores()
    print(score_manager)

    # 计算每个学生的总分并进行排名
    score_manager.calc_student_ranks()

    # 浏览查看学生信息
    print(student_manager)

    # 添加学生信息
    student_manager.add_student('20210001', '张三', '男', 20)
    data_manager.save_data(students)

    # 修改学生信息
    student_manager.modify_student('20210001', '李四', '女', 21)
    data_manager.save_data(students)

    # 删除学生信息
    student_manager.delete_student('20210001')
    data_manager.save_data(students)

    # 查询学生信息
    print(query_manager.query_by_id('20200001'))
    print(query_manager.query_by_name('张三'))
    print(query_manager.query_by_rank(1))

if __name__ == '__main__':
    main()

上述代码实现了基本的学生成绩管理系统功能，您可以根据实际需求进行修改和扩展。同时，您需要注意数据的安全性和准确性，例如数据文件的备份和防止数据丢失等。