用Python实现:假设一个班学生信息包括学号、姓名、成绩，用单链表实现对一个班的学生信息的录入、显示、查询、修改、插入、删除和按总分排名次等功能

以下是一个基本的单链表实现，其中每个节点表示一个学生信息：

class StudentNode:
    def __init__(self, id, name, score):
        self.id = id
        self.name = name
        self.score = score
        self.next = None

class StudentList:
    def __init__(self):
        self.head = None

    def add(self, node):
        if not self.head:
            self.head = node
        else:
            curr = self.head
            while curr.next:
                curr = curr.next
            curr.next = node

    def display(self):
        curr = self.head
        while curr:
            print(f"{curr.id}\t{curr.name}\t{curr.score}")
            curr = curr.next

    def search(self, id):
        curr = self.head
        while curr:
            if curr.id == id:
                return curr
            curr = curr.next
        return None

    def update(self, id, name, score):
        node = self.search(id)
        if node:
            node.name = name
            node.score = score

    def insert(self, index, node):
        if index == 0:
            node.next = self.head
            self.head = node
        else:
            curr = self.head
            while index > 1 and curr:
                curr = curr.next
                index -= 1
            if curr:
                node.next = curr.next
                curr.next = node
            else:
                self.add(node)

    def delete(self, id):
        if not self.head:
            return
        if self.head.id == id:
            self.head = self.head.next
        else:
            curr = self.head
            while curr.next and curr.next.id != id:
                curr = curr.next
            if curr.next:
                curr.next = curr.next.next

    def sort_by_score(self):
        nodes = []
        curr = self.head
        while curr:
            nodes.append(curr)
            curr = curr.next
        nodes.sort(key=lambda node: node.score, reverse=True)
        self.head = None
        for node in nodes:
            self.add(node)

然后我们可以使用这个链表来实现各种功能。例如，录入学生信息：

students = StudentList()
students.add(StudentNode(1, 'Tom', 90))
students.add(StudentNode(2, 'Jerry', 80))
students.add(StudentNode(3, 'Alice', 95))
students.add(StudentNode(4, 'Bob', 85))

显示学生信息：

students.display()

查询学生信息：

node = students.search(3)
if node:
    print(f"{node.id}\t{node.name}\t{node.score}")
else:
    print("Student not found.")

修改学生信息：

students.update(2, 'Jerry Mouse', 85)

插入学生信息：

students.insert(2, StudentNode(5, 'Eva', 92))

删除学生信息：

students.delete(1)

按总分排序：

students.sort_by_score()