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学生成绩表信息包括学号、姓名、各科课程成绩（语文、数学、英语、政治）和总分。用带头结点的单链表管理学生成绩表，每个学生的信息依次从键盘输入，并根据需要进行插入、删除、排序、输出等操作。

import json# 初始化系统
students = []# 结构体
class Student:def __init__(self, ID, Name, Mark):self.ID = IDself.Name = Nameself.Mark = Markself.Total = sum(Mark)self.Average = self.Total / len(Mark)# 录入
def inputt():global studentsID = input("请输入学号：")Name = input("请输入姓名：")Marks = []for subject in ["数学", "英语", "语文"]:mark = float(input(f"请输入{subject}成绩："))Marks.append(mark)student = Student(ID, Name, Marks)students.append(student)print("录入成功。")# 删除
def deletee():global studentsID = input("请输入要删除的学生学号：")found = Falsefor student in students:if student.ID == ID:students.remove(student)found = Trueprint("删除成功。")breakif not found:print(f"未找到学号为{ID}的学生。")# 修改
def modfiy():global studentsID = input("请输入要修改的学生学号：")found = Falsefor student in students:if student.ID == ID:Marks = []for subject in ["数学", "英语", "语文"]:mark = float(input(f"请输入新的{subject}成绩："))Marks.append(mark)student.Mark = Marksstudent.Total = sum(Marks)student.Average = student.Total / len(Marks)found = Trueprint("修改成功。")breakif not found:print(f"未找到学号为{ID}的学生。")# 插入
def insert():global studentsposition = int(input("请输入要插入的位置（1-{}）：".format(len(students) + 1)))if 1 <= position <= len(students) + 1:ID = input("请输入学号：")Name = input("请输入姓名：")Marks = []for subject in ["数学", "英语", "语文"]:mark = float(input(f"请输入{subject}成绩："))Marks.append(mark)student = Student(ID, Name, Marks)students.insert(position - 1, student)print("插入成功。")else:print("插入位置无效。")# 排序
def sort():global studentsstudents.sort(key=lambda x: x.Average, reverse=True)print("排序完成。")# 显示
def display():global studentsif not students:print("暂无学生信息。")else:print("学号\t姓名\t数学\t英语\t语文\t总分\t平均分")for student in students:print(f"{student.ID}\t{student.Name}\t{student.Mark[0]}\t{student.Mark[1]}\t{student.Mark[2]}\t{student.Total:.2f}\t{student.Average:.2f}")# 查询
def Student_SearchByIndex():global studentsID = input("请输入要查询的学生学号：")found = Falsefor student in students:if student.ID == ID:print("学号\t姓名\t数学\t英语\t语文\t总分\t平均分")print(f"{student.ID}\t{student.Name}\t{student.Mark[0]}\t{student.Mark[1]}\t{student.Mark[2]}\t{student.Total:.2f}\t{student.Average:.2f}")found = Truebreakif not found:print(f"未找到学号为{ID}的学生。")# 主函数
def main():while True:print("\n学生成绩管理系统")print("1. 录入学生信息")print("2. 删除学生信息")print("3. 修改学生成绩")print("4. 插入学生成绩")print("5. 排序学生成绩")print("6. 显示学生成绩")print("7. 查询学生成绩")print("8. 退出系统")choice = input("请选择操作（1-8）：")if choice == "1":inputt()elif choice == "2":deletee()elif choice == "3":modfiy()elif choice == "4":insert()elif choice == "5":sort()elif choice == "6":display()elif choice == "7":Student_SearchByIndex()elif choice == "8":breakelse:print("无效的选择，请重新输入。")if __name__ == "__main__":main()