[CareerCup] 8.5 Online Book Reader System 在线读书系统

亦凉 2022-02-01 01:59 42阅读 0赞

8.5 Design the data structures for an online book reader system.

这道题OOB的题让我们设计一个在线读书系统，还是没有任何提示，所以发挥空间很大。根据书上的解答，我们设计一个具有基本功能的系统：

1. 用户会员的建立和延长

2. 搜索书库中的书

3. 在线读书

4. 每次只能有一个活跃用户

5. 每个读者只能读一本书

那么最基本的先实现书类Book，和用户类User，然后是书库类Library，用户管理类UserManager，显示类Display，最后是整合类OnlineReaderSystem，具体实现代码如下：

class Book {
    public:
        Book(int id, string det): _bookId(id), _details(det) {}
        int getID() { return _bookId; }
        void setId(int id) { _bookId = id; }
        string getDetails() { return _details; }
        void setDetails(string d) { _details = d; }
    
    private:
        int _bookId;
        string _details;
    };
    
    class User {
    public:
        User(int id, string details, int accountType): _userId(id), _details(details), _accountType(accountType) {}
        void renewMembership() {}
        int getID() { return _userId; }
        void setID(int id) { _userId = id; }
        string getDetails() { return _details; }
        void setDetails(string details) { _details = details; }
        int getAccountType() { return _accountType; }
        void setAccountType(int t) { _accountType = t; }
    
    private:
        int _userId;
        string _details;
        int _accountType;
    };
    
    class Library {
    public:
        Library() {}
        Book* addBook(int id, string details) {
            if (_books.find(id) == _books.end()) return nullptr;
            Book *book = new Book(id, details);
            _books[id] = book;
            return book;
        }
        bool remove(Book *b) { return remove(b->getID()); }
        bool remove(int id) {
            if (_books.find(id) == _books.end()) return false;
            _books.erase(id);
            return true;
        }
        Book* find(int id) {
            if (_books.find(id) == _books.end()) return nullptr;
            return _books[id];
        }
    
    private:
        unordered_map<int, Book*> _books;
    };
    
    class UserManager {
    public:
        UserManager() {}
        User* addUser(int id, string details, int accountType) {
            if (_users.find(id) == _users.end()) return nullptr;
            User *user = new User(id, details, accountType);
            _users[id] = user;
            return user;
        }
        bool remove(User *u) { return remove(u->getID()); }
        bool remove(int id) {
            if (_users.find(id) == _users.end()) return false;
            _users.erase(id);
            return true;
        }
        User* find(int id) {
            if (_users.find(id) == _users.end()) return nullptr;
            return _users[id];
        }
    
    private:
        unordered_map<int, User*> _users;
    };
    
    class Display {
    public:
        Display() {}
        void displayUser(User *user) {
            _activeUser = user;
            refreshUsername();
        }
        void displayBook(Book *book) {
            _pageNumber = 0;
            _activeBook = book;
            refreshTitle();
            refreshDetails();
            refreshPage();
        }
        void turnPageForward() {
            ++_pageNumber;
            refreshPage();
        }
        void turnPageBackward() {
            --_pageNumber;
            refreshPage();
        }
        void refreshUsername() {} // ...
        void refreshTitle() {} // ...
        void refreshDetails() {} // ...
        void refreshPage() {} // ...
    
    private:
        Book *_activeBook;
        User *_activeUser;
        int _pageNumber = 0;
    };
    
    class OnlineReaderSystem {
    public:
        OnlineReader() {
            _userManager = new UserManager();
            _library = new Library();
            _display = new Display();
        }
        Library* getLibrary() { return _library; }
        UserManager* getUserManager() { return _userManager; }
        Display* getDisplay() { return _display; }
        Book* getActiveBook() { return _activeBook; }
        void setActiveBook(Book *book) {
            _activeBook = book;
            _display->displayBook(book);
        }
        User* getActiveUser() { return _activeUser; }
        void setActiveUser(User *user) {
            _activeUser = user;
            _display->displayUser(user);
        }
    
    private:
        Library *_library;
        UserManager *_userManager;
        Display *_display;
        Book *_activeBook;
        User *_activeUser;
    };

本文转自博客园Grandyang的博客，原文链接：[在线读书系统\[CareerCup\] 8.5 Online Book Reader System ][CareerCup_ 8.5 Online Book Reader System]，如需转载请自行联系原博主。

[CareerCup_ 8.5 Online Book Reader System]: http://www.cnblogs.com/grandyang/p/4790816.html