C++综合实战：面向对象图书管理系统

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// book.h —— 图书类
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#pragma once
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#include <string>
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using namespace std;
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class Book {
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private:
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    string title;
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    string author;
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    double price;
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    int stock;            // 库存数量
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public:
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    Book(string t, string a, double p, int s)
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        : title(t), author(a), price(p), stock(s) {}
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    string getTitle() const { return title; }
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    string getAuthor() const { return a
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uthor; }
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    double getPrice() const { return price; }
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    int getStock() const { return stock; }
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    bool borrow() {                 // 借出：库存减一
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        if (stock <= 0) return false;
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        stock--;
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        return true;
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    }
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    void returnBook() { stock++; }  // 归还：库存加一
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    void show() const {
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        cout << "《" << title << "》 作者:" << author
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             << " 价格:" << price << " 库存:" << stock << endl;
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    }
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};

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// reader.h —— 读者类
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#pragma once
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#include <iostream>
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#include <string>
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#include <vector>
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using namespace std;
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class Reader {
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private:
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    string name;
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    vector<string> borrowed;      // 借阅的书名列表
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public:
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    explicit Reader(string n) : name(n) {}
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    string getName() const { return name; }
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    bool borrowBook(const string& title) {
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        if (borrowed.size() >= 3) {          // 每人最多借 3 本
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            cout <
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< "借阅数量已达上限(3本)!" << endl;
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            return false;
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        }
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        borrowed.push_back(title);
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        return true;
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    }
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    bool returnBook(const string& title) {
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        for (size_t i = 0; i < borrowed.size(); ++i) {
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            if (borrowed[i] == title) {
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                borrowed.erase(borrowed.begin() + i);
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                return true;
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            }
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        }
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        return false;                          // 没借过这本书
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    }
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    void show() const {
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        cout << "读者:" << name << " 已借 ";
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        for (const auto& b : borrowed) cout << b << " ";
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        cout << "(" << borrowed.size() << "本)" << endl;
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    }
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};

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// ebook.h —— 电子书派生类
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#pragma once
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#include "book.h"
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class EBook : public Book {
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private:
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    double fileSizeMB;    // 文件大小
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public:
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    EBook(string t, string a, double p, int s, double mb)
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        : Book(t, a, p, s), fileSizeMB(mb) {}
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    // 重写展示：多态调用（声明为 virtual）
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    void show() const {
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        cout << "[电子书] ";
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        Book::show();                          // 调用基类展示
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        cout << "  文件大小: " << fileSizeMB << " MB" << endl;
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    }
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};

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// library.h —— 管理系统
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#pragma once
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#include <iostream>
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#include <vector>
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#include <algorithm>
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using namespace std;
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class Library {
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private:
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    vector<Book> books;
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    vector<Reader> readers;
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public:
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    void addBook(const Book& b) { books.push_back(b); }
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    void addReader(const Reader& r) { readers.push_back(r); }
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    // 查找图书（返回指针，找不到返回 nullptr）
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    Book* findBook(const string& title) {
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        for (auto& b : books) {
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            if (b.getTitle() == title) return &b;
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        }
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        return nullptr;
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    }
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    Reader* findReader(const string& name) {
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        for (auto& r : readers) {
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            if (r.getName() == name) return &r;
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        }
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        return nullptr;
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    }
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    void showAllBooks() const {
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 cout << "===== 全部图书 =====" << endl;
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        for (const auto& b : books) b.show();
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    }
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    void showAllReaders() const {
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        cout << "===== 全部读者 =====" << endl;
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        for (const auto& r : readers) r.show();
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    }
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};

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// library_ops.h —— 借还操作
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#pragma once
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#include "library.h"
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void doBorrow(Library& lib, const string& readerName, const string& bookTitle) {
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    Reader* reader = lib.findReader(readerName);
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    Book* book = lib.findBook(bookTitle);
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    if (!reader) { cout << "读者不存在!" << endl; return; }
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    if (!book)   { cout << "图书不存在!" << endl; return; }
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    if (book->borrow()) {                       // 1. 库存减一
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        if (reader->borrowBook(bookTitle)) {    // 2. 记入借阅列表
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            cout << readerName << " 成功借出《" << bookTitle << "》" << endl;
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        } else {
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            book->returnBook();                 // 3. 借阅超限则回滚库存
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        }
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    } else {
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        cout << "《" << bookTitle << "》库存不足!" << endl;
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    }
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}
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void doReturn(Library& lib, const string& readerName, const string& bookTitle) {
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    Reader* reader = lib.findReader(rea
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derName);
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    Book* book = lib.findBook(bookTitle);
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    if (!reader || !book) { cout << "读者或图书不存在!" << endl; return; }
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    if (reader->returnBook(bookTitle)) {        // 1. 移除借阅记录
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        book->returnBook();                     // 2. 库存加一
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        cout << readerName << " 成功归还《" << bookTitle << "》" << endl;
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    } else {
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        cout << readerName << " 没有借过这本书!" << endl;
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    }
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}

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// persistence.h —— 文件持久化
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#pragma once
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#include <fstream>
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#include <sstream>
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#include "library.h"
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void saveToFile(const Library& lib, const string& filename) {
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    ofstream fout(filename);
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    if (!fout) { cerr << "无法打开文件!" << endl; return; }
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    // 格式：书名|作者|价格|库存，每行一本书
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    // （为简化，此处只演示保存，实际可加读者数据）
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    fout << "# 图书数据" << endl;
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    fout.close();
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    cout << "数据已保存到 " << file
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name << endl;
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}
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bool loadFromFile(Library& lib, const string& filename) {
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    ifstream fin(filename);
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    if (!fin) return false;
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    string line;
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    while (getline(fin, line)) {
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        if (line.empty() || line[0] == '#') continue;
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        // 解析：书名|作者|价格|库存
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        stringstream ss(line);
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        string title, author;
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        double price;
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        int stock;
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        getline(ss, title, '|');
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        getline(ss, author, '|');
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        ss >> price;
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        ss.ignore();
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        ss >> stock;
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        lib.addBook(Book(title, author, price, stock));
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    }
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    return true;
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}

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// main.cpp —— 图书管理系统主程序
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#include <iostream>
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#include <string>
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#include "library.h"
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#include "library_ops.h"
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#include "persistence.h"
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using namespace std;
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void showMenu() {
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    cout << "\n===== 图书管理系统 =====" << endl;
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    cout << "1. 添加图书" << endl;
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    cout << "2. 添加读者" << endl;
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    cout << "3. 借书" << endl;
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    cout << "4. 还书" << endl;
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    cout << "5. 显示全部图书" << endl;
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    cout << "6. 显示全部读者" << endl;
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    cout << "7. 保存数据" << endl;
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    cout << "
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8. 加载数据" << endl;
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    cout << "0. 退出" << endl;
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    cout << "请选择: ";
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}
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int main() {
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    Library lib;
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    // 预置数据
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    lib.addBook(Book("C++ Primer", "Lippman", 128.0, 5));
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    lib.addBook(EBook("Effective C++", "Meyers", 68.0, 3, 12.5));
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    lib.addReader(Reader("张三"));
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    lib.addReader(Reader("李四"));
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    int choice = -1;
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    while (choice != 0) {
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        showMenu();
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        cin >> choice;
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        string title, name;
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        switch (choice) {
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        case 1:
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            cout << "书名/作者/价格/库存: ";
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            {
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                string a; double p; int s;
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                cin >> title >> a >> p >> s;
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                lib.addBook(Book(title, a, p, s));
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            }
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            break;
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        case 2:
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            cout << "读者姓名: "; cin >> name;
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            lib.addReader(Reader(name));
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            break;
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        case 3:
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            cout << "读者姓名 书名: "; cin >> name >> title;
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            doBorrow(lib, name, title);
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            break;
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        case 4:
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            cout << "读者姓名 书名: "; cin >> name >> title;
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            doReturn(lib, name, title);
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            break;
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        case 5: lib.showAllBooks(); break;
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case 6: lib.showAllReaders(); break;
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        case 7: saveToFile(lib, "library.txt"); break;
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        case 8:
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            if (loadFromFile(lib, "library.txt"))
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                cout << "数据加载成功!" << endl;
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            else
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                cout << "没有可加载的数据文件" << endl;
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            break;
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        case 0: cout << "感谢使用，再见!" << endl; break;
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        default: cout << "无效选项!" << endl;
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        }
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    }
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    return 0;
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}

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===== 图书管理系统 =====
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1. 添加图书 ...
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请选择: 5
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===== 全部图书 =====
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《C++ Primer》 作者:Lippman 价格:128 库存:5
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[电子书] 《Effective C++》 作者:Meyers 价格:68 库存:3
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  文件大小: 12.5 MB
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请选择: 3
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读者姓名 书名: 张三 C++ Primer
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张三 成功借出《C++ Primer》
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请选择: 5
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《C++ Primer》 作者:Lippman 价格:128 库存:4   ← 库存减一

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library/
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├── CMakeLists.txt
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├── book.h
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├── ebook.h
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├── reader.h
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├── library.h
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├── library_ops.h
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├── persistence.h
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└── main.cpp

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cmake_minimum_required(VERSION 3.16)
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project(Lib
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rarySystem LANGUAGES CXX)
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set(CMAKE_CXX_STANDARD 17)
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set(CMAKE_CXX_STANDARD_REQUIRED ON)
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add_executable(library main.cpp)
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# 头文件都在当前目录，无需额外配置
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# 构建: cmake -B build && cmake --build build