构建一个班级信息链表类，学生信息包括：学号（ID）、姓名（Name）、出生年月（Birth）、性别(Sex)和某门功课成绩（Score）。类的成员函数只需要满足本题要求即可，学生人数由用户决定。为避免大量输入工作，建议学生信息从文件读入，文件格式可自行设定并描述清楚。实现：（1）按成绩降序排列，（2）汇总各分数段人数。分数段划分区间为[90,100]，[80,90)，[70,80), [60,70), [0,60)，(3)列出最高分和最低分的同学信息。（注：不允许使用STL，否则不计成绩）

好的，我可以帮你解决这个问题。以下是班级信息链表类的实现，包括文件读入、成绩降序排列、分数段汇总和最高分、最低分同学信息的列出：

#include <iostream>
#include <fstream>
#include <string>

using namespace std;

struct Student {
    int ID;
    string Name;
    string Birth;
    string Sex;
    int Score;
    Student* next;
};

class StudentList {
private:
    Student* head;
    int size;
public:
    StudentList() {
        head = nullptr;
        size = 0;
    }

    void insert(int id, string name, string birth, string sex, int score) {
        Student* newStudent = new Student;
        newStudent->ID = id;
        newStudent->Name = name;
        newStudent->Birth = birth;
        newStudent->Sex = sex;
        newStudent->Score = score;
        newStudent->next = nullptr;

        if (head == nullptr) {
            head = newStudent;
        }
        else {
            Student* current = head;
            while (current->next != nullptr) {
                current = current->next;
            }
            current->next = newStudent;
        }

        size++;
    }

    void readFromFile(string filename) {
        ifstream input(filename);
        if (!input) {
            cout << "Error opening file." << endl;
            return;
        }

        int id, score;
        string name, birth, sex;
        while (input >> id >> name >> birth >> sex >> score) {
            insert(id, name, birth, sex, score);
        }

        input.close();
    }

    void sortByScore() {
        for (Student* i = head; i != nullptr; i = i->next) {
            for (Student* j = i->next; j != nullptr; j = j->next) {
                if (j->Score > i->Score) {
                    int tempID = i->ID;
                    string tempName = i->Name;
                    string tempBirth = i->Birth;
                    string tempSex = i->Sex;
                    int tempScore = i->Score;

                    i->ID = j->ID;
                    i->Name = j->Name;
                    i->Birth = j->Birth;
                    i->Sex = j->Sex;
                    i->Score = j->Score;

                    j->ID = tempID;
                    j->Name = tempName;
                    j->Birth = tempBirth;
                    j->Sex = tempSex;
                    j->Score = tempScore;
                }
            }
        }
    }

    void countByScore() {
        int count[6] = {0};
        for (Student* i = head; i != nullptr; i = i->next) {
            if (i->Score >= 90) {
                count[0]++;
            }
            else if (i->Score >= 80) {
                count[1]++;
            }
            else if (i->Score >= 70) {
                count[2]++;
            }
            else if (i->Score >= 60) {
                count[3]++;
            }
            else {
                count[4]++;
            }
        }

        count[5] = size - count[0] - count[1] - count[2] - count[3] - count[4];

        cout << "90-100: " << count[0] << endl;
        cout << "80-89: " << count[1] << endl;
        cout << "70-79: " << count[2] << endl;
        cout << "60-69: " << count[3] << endl;
        cout << "0-59: " << count[4] << endl;
        cout << "Total: " << count[5] << endl;
    }

    void printHighestAndLowest() {
        Student* highest = head;
        Student* lowest = head;
        for (Student* i = head->next; i != nullptr; i = i->next) {
            if (i->Score > highest->Score) {
                highest = i;
            }
            if (i->Score < lowest->Score) {
                lowest = i;
            }
        }

        cout << "Highest: " << highest->ID << " " << highest->Name << " " << highest->Birth << " " << highest->Sex << " " << highest->Score << endl;
        cout << "Lowest: " << lowest->ID << " " << lowest->Name << " " << lowest->Birth << " " << lowest->Sex << " " << lowest->Score << endl;
    }
};

班级信息链表类包含一个 `Student` 结构体和一个 `StudentList` 类。`Student` 结构体表示学生信息，`next` 指向下一个学生结点。`StudentList` 类包含头结点 `head` 和链表大小 `size`，同时定义了一些成员函数来实现题目要求：

- `insert` 函数：将一个学生信息插入链表中。
- `readFromFile` 函数：从文件中读入学生信息并插入到链表中。
- `sortByScore` 函数：按成绩降序排列链表。
- `countByScore` 函数：汇总各分数段人数。
- `printHighestAndLowest` 函数：列出最高分和最低分的同学信息。

以上各函数的具体实现细节见代码注释。以下是一个使用示例：

int main() {
    StudentList list;
    list.readFromFile("students.txt");

    list.sortByScore();
    list.countByScore();
    list.printHighestAndLowest();

    return 0;
}

这个示例用 `readFromFile` 函数从文件 `students.txt` 中读入学生信息，然后用 `sortByScore` 函数按成绩降序排列，用 `countByScore` 函数汇总各分数段人数，用 `printHighestAndLowest` 函数列出最高分和最低分的同学信息。