C++代码编写模拟华业生选择指导老师提供的毕业课题。老师可增加、删除、修改课题，学生可选择课题，老师和学生都可 以查看当前己经选择的结果。

好的，以下是我给出的一份C++代码，用于模拟华业生选择指导老师提供的毕业课题：

#include <iostream>
#include <string>
#include <vector>
#include <map>

using namespace std;

// 定义老师类
class Teacher {
public:
    Teacher(int id, string name, string title, string contact) {
        this->id = id;
        this->name = name;
        this->title = title;
        this->contact = contact;
    }

    void addTopic(int topicId, string topicName, string topicDesc) {
        topics[topicId] = {topicName, topicDesc};
    }

    void deleteTopic(int topicId) {
        topics.erase(topicId);
    }

    void modifyTopic(int topicId, string topicName, string topicDesc) {
        topics[topicId] = {topicName, topicDesc};
    }

    const map<int, pair<string, string>>& getTopics() const {
        return topics;
    }

private:
    int id;
    string name;
    string title;
    string contact;
    map<int, pair<string, string>> topics; // key: topicId, value: {topicName, topicDesc}
};

// 定义学生类
class Student {
public:
    Student(int id, string name, string cls, string contact) {
        this->id = id;
        this->name = name;
        this->cls = cls;
        this->contact = contact;
    }

    void selectTopic(int topicId) {
        selectedTopics.push_back(topicId);
    }

    const vector<int>& getSelectedTopics() const {
        return selectedTopics;
    }

private:
    int id;
    string name;
    string cls;
    string contact;
    vector<int> selectedTopics; // 已选课题的topicId列表
};

// 定义课题选题系统类
class TopicSelectSystem {
public:
    void addTeacher(int id, string name, string title, string contact) {
        teachers[id] = new Teacher(id, name, title, contact);
    }

    void deleteTeacher(int id) {
        auto it = teachers.find(id);
        if (it != teachers.end()) {
            delete it->second;
            teachers.erase(it);
        }
    }

    void modifyTeacher(int id, string name, string title, string contact) {
        auto it = teachers.find(id);
        if (it != teachers.end()) {
            it->second = new Teacher(id, name, title, contact);
        }
    }

    void addTopic(int teacherId, int topicId, string topicName, string topicDesc) {
        auto it = teachers.find(teacherId);
        if (it != teachers.end()) {
            it->second->addTopic(topicId, topicName, topicDesc);
            topics[topicId] = teacherId;
        }
    }

    void deleteTopic(int topicId) {
        auto it = topics.find(topicId);
        if (it != topics.end()) {
            int teacherId = it->second;
            auto itt = teachers.find(teacherId);
            if (itt != teachers.end()) {
                itt->second->deleteTopic(topicId);
            }
            topics.erase(it);
        }
    }

    void modifyTopic(int topicId, string topicName, string topicDesc) {
        auto it = topics.find(topicId);
        if (it != topics.end()) {
            int teacherId = it->second;
            auto itt = teachers.find(teacherId);
            if (itt != teachers.end()) {
                itt->second->modifyTopic(topicId, topicName, topicDesc);
            }
        }
    }

    void selectTopic(int studentId, int topicId) {
        auto it = students.find(studentId);
        if (it != students.end()) {
            it->second->selectTopic(topicId);
        }
    }

    void addStudent(int id, string name, string cls, string contact) {
        students[id] = new Student(id, name, cls, contact);
    }

    void deleteStudent(int id) {
        auto it = students.find(id);
        if (it != students.end()) {
            delete it->second;
            students.erase(it);
        }
    }

    void modifyStudent(int id, string name, string cls, string contact) {
        auto it = students.find(id);
        if (it != students.end()) {
            it->second = new Student(id, name, cls, contact);
        }
    }

    void printTopics() {
        for (auto& p : topics) {
            int topicId = p.first;
            int teacherId = p.second;
            auto it = teachers.find(teacherId);
            if (it != teachers.end()) {
                Teacher* teacher = it->second;
                const map<int, pair<string, string>>& topics = teacher->getTopics();
                auto itt = topics.find(topicId);
                if (itt != topics.end()) {
                    const pair<string, string>& topic = itt->second;
                    cout << "Topic ID: " << topicId << ", Topic Name: " << topic.first << ", Topic Desc: " << topic.second << ", Teacher: " << teacher->getTopics() << endl;
                }
            }
        }
    }

    void printSelectedTopics(int studentId) {
        auto it = students.find(studentId);
        if (it != students.end()) {
            Student* student = it->second;
            const vector<int>& selectedTopics = student->getSelectedTopics();
            cout << "Selected Topics for Student " << studentId << ":" << endl;
            for (int topicId : selectedTopics) {
                auto itt = topics.find(topicId);
                if (itt != topics.end()) {
                    int teacherId = itt->second;
                    auto ittt = teachers.find(teacherId);
                    if (ittt != teachers.end()) {
                        Teacher* teacher = ittt->second;
                        const map<int, pair<string, string>>& topics = teacher->getTopics();
                        auto itttt = topics.find(topicId);
                        if (itttt != topics.end()) {
                            const pair<string, string>& topic = itttt->second;
                            cout << "Topic ID: " << topicId << ", Topic Name: " << topic.first << ", Topic Desc: " << topic.second << ", Teacher: " << teacher->getTopics() << endl;
                        }
                    }
                }
            }
        }
    }

private:
    map<int, Teacher*> teachers; // key: teacherId, value: Teacher*
    map<int, int> topics; // key: topicId, value: teacherId
    map<int, Student*> students; // key: studentId, value: Student*
};

int main() {
    TopicSelectSystem system;

    // 添加老师
    system.addTeacher(1, "Tom", "Professor", "123456");
    system.addTeacher(2, "Jerry", "Associate Professor", "234567");

    // 添加课题
    system.addTopic(1, 1, "Topic 1", "Topic 1 Desc");
    system.addTopic(1, 2, "Topic 2", "Topic 2 Desc");
    system.addTopic(2, 3, "Topic 3", "Topic 3 Desc");

    // 输出课题列表
    system.printTopics();

    // 添加学生
    system.addStudent(1, "Alice", "Class 1", "345678");
    system.addStudent(2, "Bob", "Class 2", "456789");

    // 学生选课
    system.selectTopic(1, 1);
    system.selectTopic(1, 2);
    system.selectTopic(2, 3);

    // 输出学生已选课题列表
    system.printSelectedTopics(1);
    system.printSelectedTopics(2);

    return 0;
}

以上代码实现了一个简单的课题选题系统，包括添加、删除、修改老师和课题，以及学生选择课题和输出学生已选课题列表等功能。