C++ 实现图书馆资料管理系统

1、问题描述 ：

图书馆中的资料很多，如果能分类对其资料流通进行管理，将会带来很多方 便，因此需要有一个媒体库管理系统。 图书馆共有三大类物品资料：图书、视频光盘、图画。 这三类物品共同具有的属性有：编号、标题、作者、评级（未评级，一般 成人，儿童） 等。其中图书类增加出版社、ISBN号、页数等信息；视频光盘类增加出品者 的名字、出品年份和视频时长等信息；图画类增加出品国籍、作品的长和宽 （以厘米计，整数）等信息。 读者：基本信息，可借阅本数 管理员：负责借阅

2、功能要求 ：

(1)添加物品：主要完成图书馆三类物品信息的添加，要求编号唯一。当添 加了重复的编号时，则提示数据添加重复并取消添加：查询物品可按照三种 方式来查询物品，分别为： 按标题查询：输入标题，输出所查询的信息，若不存在该记录，则提示“该 标题+存在！”； 按编号查询：输入编号，输出所查询的信息，若不存在该记录，则提示“该 编号不存在！”； 按类别查询：输入类别，输出所查询的信息，若不存在记录，则提示“该类 别没有物品！”；

(2)显示物品库：输出当前物品库中所有物品信息，每条记录占据一行。

(3)编辑物品：可根据查询结果对相应的记录进行修改，修改时注意编号的 唯一性。

(4)删除物品：主要完成图书馆物品信息的删除。如果当前物品库为空，则 提示“物品库为空！”，并返回操作：否则，输入要删除的编号，根据编号删 除该物品的记录，如果该编号不在物品库中，则提示“该编号不存在”。

(5)借阅，管理员负责将物品借阅给读者，数据保存到文件中 。

(6)统计信息 输出当前物品库中总物品数，以及按物品类别，统计出山前物品中各类别的 物品数并显。

(7)物品存盘：将当前程序中的物品信息存入文件中。

(8)读出物品 从文件中将物品信息读入程序。 开发完代码后需要进行测试，如果报错请修改，知道各项功能都可以正常运行。

#include 
#include 
#include 
#include 
#include 
#include 
using namespace std;
 
enum Rating { UNRATED, ADULT, CHILD };
 
string ratingToString(Rating rating) {
    switch (rating) {
        case UNRATED: return "未评级";
        case ADULT: return "成人";
        case CHILD: return "儿童";
        default: return "";
    }
}
 
class Media {
public:
    int id;
    string title;
    string author;
    Rating rating;
 
    Media(int id, string title, string author, Rating rating)
        : id(id), title(title), author(author), rating(rating) {}
 
    virtual void display() const {
        cout << "ID: " << id << ", 标题: " << title << ", 作者: " << author << ", 评级: " << ratingToString(rating) << endl;
    }
 
    virtual ~Media() {}
};
 
class Book : public Media {
public:
    string publisher;
    string isbn;
    int pages;
 
    Book(int id, string title, string author, Rating rating, string publisher, string isbn, int pages)
        : Media(id, title, author, rating), publisher(publisher), isbn(isbn), pages(pages) {}
 
    void display() const override {
        Media::display();
        cout << "出版社: " << publisher << ", ISBN: " << isbn << ", 页数: " << pages << endl;
    }
};
 
class Video : public Media {
public:
    string producer;
    int year;
    int duration;
 
    Video(int id, string title, string author, Rating rating, string producer, int year, int duration)
        : Media(id, title, author, rating), producer(producer), year(year), duration(duration) {}
 
    void display() const override {
        Media::display();
        cout << "出品者: " << producer << ", 年份: " << year << ", 时长: " << duration << " mins" << endl;
    }
};
 
class Picture : public Media {
public:
    string nationality;
    int length;
    int width;
 
    Picture(int id, string title, string author, Rating rating, string nationality, int length, int width)
        : Media(id, title, author, rating), nationality(nationality), length(length), width(width) {}
 
    void display() const override {
        Media::display();
        cout << "国籍: " << nationality << ", 尺寸: " << length << "x" << width << " cm" << endl;
    }
};
 
class Library {
    unordered_map<int, Media*> mediaCollection;
 
public:
    ~Library() {
        for (auto& pair : mediaCollection) {
            delete pair.second;
        }
    }
 
    void addMedia(Media* media) {
        if (mediaCollection.find(media->id) != mediaCollection.end()) {
            cout << "检测到重复的 ID, 未添加资料." << endl;
            delete media;
            return;
        }
        mediaCollection[media->id] = media;
        cout << "资料添加成功." << endl;
    }
 
    void queryByTitle(const string& title) {
        bool found = false;
        for (const auto& pair : mediaCollection) {
            if (pair.second->title == title) {
                pair.second->display();
                found = true;
            }
        }
        if (!found) cout << " 标题 \"" << title << "\" 不存在!" << endl;
    }
 
    void queryById(int id) {
        if (mediaCollection.find(id) != mediaCollection.end()) {
            mediaCollection[id]->display();
        } else {
            cout << " ID \"" << id << "\" 不存在!" << endl;
        }
    }
 
    void queryByType(const string& type) {
        bool found = false;
        for (const auto& pair : mediaCollection) {
            if ((type == "Book" && dynamic_cast(pair.second)) ||
                (type == "Video" && dynamic_cast(pair.second)) ||
                (type == "Picture" && dynamic_cast(pair.second))) {
                pair.second->display();
                found = true;
            }
        }
        if (!found) cout << "分类没有 \"" << type << "\" 找到!" << endl;
    }
 
    void displayAll() {
        if (mediaCollection.empty()) {
            cout << "数据库中没有相关资料." << endl;
            return;
        }
        for (const auto& pair : mediaCollection) {
            pair.second->display();
        }
    }
 
    void editMedia(int id, Media* newMedia) {
        if (mediaCollection.find(id) == mediaCollection.end()) {
            cout << " ID \"" << id << "\" 不存在!" << endl;
            delete newMedia;
            return;
        }
        delete mediaCollection[id];
        mediaCollection[id] = newMedia;
        cout << "资料编辑成功." << endl;
    }
 
    void deleteMedia(int id) {
        if (mediaCollection.find(id) == mediaCollection.end()) {
            cout << " ID \"" << id << "\" 不存在!" << endl;
            return;
        }
        delete mediaCollection[id];
        mediaCollection.erase(id);
        cout << "资料删除成功." << endl;
    }
 
    void saveToFile(const string& filename) {
        ofstream file(filename, ios::binary);
        if (!file) {
            cout << "无法打开文件进行写入." << endl;
            return;
        }
        for (const auto& pair : mediaCollection) {
            Media* media = pair.second;
            file.write((char*)&media->id, sizeof(media->id));
            size_t length = media->title.size();
            file.write((char*)&length, sizeof(length));
            file.write(media->title.c_str(), length);
            length = media->author.size();
            file.write((char*)&length, sizeof(length));
            file.write(media->author.c_str(), length);
            file.write((char*)&media->rating, sizeof(media->rating));
 
            if (Book* book = dynamic_cast(media)) {
                char type = 'B';
                file.write(&type, sizeof(type));
                length = book->publisher.size();
                file.write((char*)&length, sizeof(length));
                file.write(book->publisher.c_str(), length);
                length = book->isbn.size();
                file.write((char*)&length, sizeof(length));
                file.write(book->isbn.c_str(), length);
                file.write((char*)&book->pages, sizeof(book->pages));
            } else if (Video* video = dynamic_cast(media)) {
                char type = 'V';
                file.write(&type, sizeof(type));
                length = video->producer.size();
                file.write((char*)&length, sizeof(length));
                file.write(video->producer.c_str(), length);
                file.write((char*)&video->year, sizeof(video->year));
                file.write((char*)&video->duration, sizeof(video->duration));
            } else if (Picture* picture = dynamic_cast(media)) {
                char type = 'P';
                file.write(&type, sizeof(type));
                length = picture->nationality.size();
                file.write((char*)&length, sizeof(length));
                file.write(picture->nationality.c_str(), length);
                file.write((char*)&picture->length, sizeof(picture->length));
                file.write((char*)&picture->width, sizeof(picture->width));
            }
        }
        cout << "数据保存到文件." << endl;
    }
 
    void loadFromFile(const string& filename) {
        ifstream file(filename, ios::binary);
        if (!file) {
            cout << "无法打开文件进行读取." << endl;
            return;
        }
        while (file.peek() != EOF) {
            int id;
            file.read((char*)&id, sizeof(id));
 
            size_t length;
            file.read((char*)&length, sizeof(length));
            string title(length, ' ');
            file.read(&title[0], length);
 
            file.read((char*)&length, sizeof(length));
            string author(length, ' ');
            file.read(&author[0], length);
 
            Rating rating;
            file.read((char*)&rating, sizeof(rating));
 
            char type;
            file.read(&type, sizeof(type));
 
            if (type == 'B') {
                file.read((char*)&length, sizeof(length));
                string publisher(length, ' ');
                file.read(&publisher[0], length);
 
                file.read((char*)&length, sizeof(length));
                string isbn(length, ' ');
                file.read(&isbn[0], length);
 
                int pages;
                file.read((char*)&pages, sizeof(pages));
 
                mediaCollection[id] = new Book(id, title, author, rating, publisher, isbn, pages);
            } else if (type == 'V') {
                file.read((char*)&length, sizeof(length));
                string producer(length, ' ');
                file.read(&producer[0], length);
 
                int year, duration;
                file.read((char*)&year, sizeof(year));
                file.read((char*)&duration, sizeof(duration));
 
                mediaCollection[id] = new Video(id, title, author, rating, producer, year, duration);
            } else if (type == 'P') {
                file.read((char*)&length, sizeof(length));
                string nationality(length, ' ');
                file.read(&nationality[0], length);
 
                int length, width;
                file.read((char*)&length, sizeof(length));
                file.read((char*)&width, sizeof(width));
 
                mediaCollection[id] = new Picture(id, title, author, rating, nationality, length, width);
            }
        }
        cout << "从文件加载的数据." << endl;
    }
 
    void countItems() {
        cout << "Total items: " << mediaCollection.size() << endl;
        int books = 0, videos = 0, pictures = 0;
        for (const auto& pair : mediaCollection) {
            if (dynamic_cast(pair.second)) books++;
            else if (dynamic_cast(pair.second)) videos++;
            else if (dynamic_cast(pair.second)) pictures++;
        }
        cout << "Books: " << books << ", Videos: " << videos << ", Pictures: " << pictures << endl;
    }
};
 
int main() {
    SetConsoleOutputCP(65001);
    Library library;
    while (true) {
        cout << "欢迎使用图书馆资料管理系统: \n1. 添加资料\n2. 按标题查询资料\n3. 按ID查询资料\n4. 按类别查询资料\n5. 显示所有资料\n6. 编辑资料\n7. 删除资料\n8. 资料存盘\n9. 读取资料\n10. 统计资料\n11. 退出\n";
        int choice;
        cin >> choice;
 
        if (choice == 1) {
            cout << "选择类别: 1. 图书 2. 视频 3. 图画\n";
            int type;
            cin >> type;
            int id;
            string title, author;
            int rating;
            cout << "输入ID: ";
            cin >> id;
            cout << "输入标题: ";
            cin.ignore();
            getline(cin, title);
            cout << "输入作者: ";
            getline(cin, author);
            cout << "输入评级 (0 未评级, 1 成人, 2 儿童): ";
            cin >> rating;
 
            if (type == 1) {
                string publisher, isbn;
                int pages;
                cout << "输入出版社: ";
                cin.ignore();
                getline(cin, publisher);
                cout << "输入ISBN: ";
                getline(cin, isbn);
                cout << "输入页数: ";
                cin >> pages;
                library.addMedia(new Book(id, title, author, static_cast(rating), publisher, isbn, pages));
            } else if (type == 2) {
                string producer;
                int year, duration;
                cout << "输入出品者: ";
                cin.ignore();
                getline(cin, producer);
                cout << "输入出品年份: ";
                cin >> year;
                cout << "输入时长(分钟): ";
                cin >> duration;
                library.addMedia(new Video(id, title, author, static_cast(rating), producer, year, duration));
            } else if (type == 3) {
                string nationality;
                int length, width;
                cout << "输入出品国籍: ";
                cin.ignore();
                getline(cin, nationality);
                cout << "输入长度(厘米): ";
                cin >> length;
                cout << "输入宽度（厘米): ";
                cin >> width;
                library.addMedia(new Picture(id, title, author, static_cast(rating), nationality, length, width));
            }
        } else if (choice == 2) {
            string title;
            cout << "输入标题: ";
            cin.ignore();
            getline(cin, title);
            library.queryByTitle(title);
        } else if (choice == 3) {
            int id;
            cout << "输入ID: ";
            cin >> id;
            library.queryById(id);
        } else if (choice == 4) {
            string type;
            cout << "输入类别 (图书, 视频, 图画): ";
            cin.ignore();
            getline(cin, type);
            library.queryByType(type);
        } else if (choice == 5) {
            library.displayAll();
        } else if (choice == 6) {
            int id;
            cout << "输入要编辑资料的ID: ";
            cin >> id;
            cout << "选择新分类: 1. 图书 2. 视频 3. 图画\n";
            int type;
            cin >> type;
            string title, author;
            int rating;
            cout << "输入新标题: ";
            cin.ignore();
            getline(cin, title);
            cout << "输入新作者: ";
            getline(cin, author);
            cout << "输入新评级 (0 未评级, 1 成人, 2 儿童): ";
            cin >> rating;
 
            if (type == 1) {
                string publisher, isbn;
                int pages;
                cout << "输入新的出版社: ";
                cin.ignore();
                getline(cin, publisher);
                cout << "输入新的ISBN: ";
                getline(cin, isbn);
                cout << "输入新的页数: ";
                cin >> pages;
                library.editMedia(id, new Book(id, title, author, static_cast(rating), publisher, isbn, pages));
            } else if (type == 2) {
                string producer;
                int year, duration;
                cout << "输入新的作者: ";
                cin.ignore();
                getline(cin, producer);
                cout << "输入新的年份: ";
                cin >> year;
                cout << "输入新的持续时间（分钟）: ";
                cin >> duration;
                library.editMedia(id, new Video(id, title, author, static_cast(rating), producer, year, duration));
            } else if (type == 3) {
                string nationality;
                int length, width;
                cout << "输入新国籍: ";
                cin.ignore();
                getline(cin, nationality);
                cout << "输入新长度（厘米）: ";
                cin >> length;
                cout << "输入新宽度（厘米）: ";
                cin >> width;
                library.editMedia(id, new Picture(id, title, author, static_cast(rating), nationality, length, width));
            }
        } else if (choice == 7) {
            int id;
            cout << "输入要删除的资料ID: ";
            cin >> id;
            library.deleteMedia(id);
        } else if (choice == 8) {
            string filename;
            cout << "输入文件名: ";
            cin.ignore();
            getline(cin, filename);
            library.saveToFile(filename);
        } else if (choice == 9) {
            string filename;
            cout << "输入文件名: ";
            cin.ignore();
            getline(cin, filename);
            library.loadFromFile(filename);
        } else if (choice == 10) {
            library.countItems();
        } else if (choice == 11) {
            break;
        } else {
            cout << "无效的选择,请再试一次." << endl;
        }
    }
 
    return 0;
}

3、运行效果：

录入：

统计：

查询：

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