编写代码实现现在某个学院有20名同学分属于2个班级（Class1 和Class2，每个班有10名同学，每个同学记录包括：班级、学号、姓名、性别、电话号码等信息）。 3．以学号为主关键字，以班级为次关键字，建立一个顺序表，表中的每个数据元素是一个记录，其中的某个域用来存储关键字的值，按关键字的值进行顺序查找。为分析排序方法的稳定性，关键字可用次关键字。 4．完成如下函数创建函数，查找函数，摧毁函数和遍历函数（其中查找函数用顺序查询和折半查询两种方式实现）

以下是 C++ 代码实现：

#include <iostream>
#include <string>
#include <algorithm>
using namespace std;

const int MAXSIZE = 20;

struct Student {
    string class_name;
    int id;
    string name;
    char gender;
    string phone;
};

struct SeqList {
    Student data[MAXSIZE];
    int length;
};

bool cmp(const Student& a, const Student& b) {
    if (a.class_name == b.class_name) {
        return a.id < b.id;
    }
    return a.class_name < b.class_name;
}

void create(SeqList& list) {
    list.length = 0;
    for (int i = 0; i < 10; i++) {
        Student s;
        s.class_name = "Class1";
        s.id = i + 1;
        s.name = "Student" + to_string(s.id);
        s.gender = 'M';
        s.phone = "123456789";
        list.data[list.length++] = s;
    }
    for (int i = 0; i < 10; i++) {
        Student s;
        s.class_name = "Class2";
        s.id = i + 1;
        s.name = "Student" + to_string(s.id);
        s.gender = 'F';
        s.phone = "987654321";
        list.data[list.length++] = s;
    }
    sort(list.data, list.data + list.length, cmp);
}

int search_seq(SeqList& list, int id) {
    for (int i = 0; i < list.length; i++) {
        if (list.data[i].id == id) {
            return i;
        }
    }
    return -1;
}

int search_bin(SeqList& list, int id) {
    int left = 0, right = list.length - 1;
    while (left <= right) {
        int mid = (left + right) / 2;
        if (list.data[mid].id == id) {
            return mid;
        } else if (list.data[mid].id > id) {
            right = mid - 1;
        } else {
            left = mid + 1;
        }
    }
    return -1;
}

void destroy(SeqList& list) {
    list.length = 0;
}

void traverse(SeqList& list) {
    for (int i = 0; i < list.length; i++) {
        cout << "Class: " << list.data[i].class_name
             << ", ID: " << list.data[i].id
             << ", Name: " << list.data[i].name
             << ", Gender: " << list.data[i].gender
             << ", Phone: " << list.data[i].phone << endl;
    }
}

int main() {
    SeqList list;
    create(list);
    traverse(list);
    int id = 5;
    int index_seq = search_seq(list, id);
    int index_bin = search_bin(list, id);
    if (index_seq == -1) {
        cout << "Not found (sequential search)" << endl;
    } else {
        cout << "Found (sequential search): " << index_seq << endl;
    }
    if (index_bin == -1) {
        cout << "Not found (binary search)" << endl;
    } else {
        cout << "Found (binary search): " << index_bin << endl;
    }
    destroy(list);
    return 0;
}

这个程序实现了创建一个顺序表，包含 20 名学生的信息，通过学号和班级进行排序。然后实现了两种查找函数，分别是顺序查找和折半查找。最后实现了摧毁函数和遍历函数。你可以按照自己的需要修改和调整这个程序。