项目案例一：基于C++的图书馆管理系统

#include <iostream>
#include <fstream>
#include <sstream>
#include <vector>

using namespace std;

// Book类表示图书对象
class Book {
private:
    string title;  // 图书标题
    string author;  // 作者
    bool isAvailable;  // 可借状态

public:
    Book(const string& title, const string& author)
        : title(title), author(author), isAvailable(true) {}

    string getTitle() const { return title; }  // 获取图书标题
    string getAuthor() const { return author; }  // 获取作者
    bool getAvailability() const { return isAvailable; }  // 获取可借状态
    void setAvailability(bool availability) { isAvailable = availability; }  // 设置可借状态

    // 输出图书信息到控制台
    void display() const {
        cout << "Title: " << title << endl;
        cout << "Author: " << author << endl;
        string availability = isAvailable ? "Available" : "Not Available";
        cout << "Availability: " << availability << endl;
    }
};

// Library类表示整个图书馆
class Library {
private:
    vector<Book> books;  // 图书集合

public:
    // 添加图书到图书馆
    void addBook(const Book& book) {
        books.push_back(book);
    }

    // 借阅图书
    void borrowBook(const string& title) {
        for (auto& book : books) {
            if (book.getTitle() == title && book.getAvailability()) {
                book.setAvailability(false);
                break;
            }
        }
    }

    // 归还图书
    void returnBook(const string& title) {
        for (auto& book : books) {
            if (book.getTitle() == title && !book.getAvailability()) {
                book.setAvailability(true);
                break;
            }
        }
    }

    // 显示所有图书信息
    void displayAllBooks() const {
        for (const auto& book : books) {
            book.display();
            cout << endl;
        }
    }
};

// 从文件中读取数据
vector<string> readDataFromFile(const string& filename) {
    ifstream file(filename);  // 打开文件流
    vector<string> data;

    if (file.is_open()) {
        string line;
        while (getline(file, line)) {  // 逐行读取文件内容
            data.push_back(line);
        }
        file.close();  // 关闭文件流
    }

    return data;
}

// 将数据追加到文件末尾
void appendDataToFile(const string& filename, const string& data) {
    ofstream file(filename, ios::app);  // 打开文件流，并将写入位置设为文件末尾
    if (file.is_open()) {
        file << data << endl;  // 写入数据
        file.close();  // 关闭文件流
    }
}

int main() {
    Library library;  // 创建 Library 对象

    vector<string> previousData = readDataFromFile("library.txt");  // 读取之前的操作记录

    // 添加之前的图书到图书馆
    for (const auto& line : previousData) {
        istringstream iss(line);  // 将每行数据拆分为标题和作者
        string title, author;
        getline(iss, title, ',');
        getline(iss, author);
        library.addBook(Book(title, author));
    }

    int choice;
    while (true) {
        cout << "Library Management System" << endl;
        cout << "1. Add Book" << endl;
        cout << "2. Borrow Book" << endl;
        cout << "3. Return Book" << endl;
        cout << "4. Display All Books" << endl;
        cout << "5. Exit" << endl;
        cout << "Enter your choice: ";
        cin >> choice;

        switch (choice) {
            case 1: {
                cout << "Enter book title: ";
                cin.ignore();  // 忽略之前的输入缓冲区
                string title;
                getline(cin, title);

                cout << "Enter author name: ";
                string author;
                getline(cin, author);

                library.addBook(Book(title, author));
                appendDataToFile("library.txt", "Added Book - Title: " + title + ", Author: " + author);
                break;
            }
            case 2: {
                cout << "Enter book title to borrow: ";
                cin.ignore();
                string title;
                getline(cin, title);

                library.borrowBook(title);
                appendDataToFile("library.txt", "Borrowed Book - Title: " + title);
                break;
            }
            case 3: {
                cout << "Enter book title to return: ";
                cin.ignore();
                string title;
                getline(cin, title);

                library.returnBook(title);
                appendDataToFile("library.txt", "Returned Book - Title: " + title);
                break;
            }
            case 4:
                library.displayAllBooks();
                break;
            case 5:
                return 0;
            default:
                cout << "Invalid choice. Please try again." << endl;
        }

        cout << endl;
    }
}

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 1
Enter book title: Harry Potter and the Philosopher's Stone
Enter author name: J.K. Rowling

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 1
Enter book title: To Kill a Mockingbird
Enter author name: Harper Lee

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 2
Enter book title to borrow: To Kill a Mockingbird

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 4
Title: Harry Potter and the Philosopher's Stone
Author: J.K. Rowling
Availability: Available

Title: To Kill a Mockingbird
Author: Harper Lee
Availability: Not Available

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 3
Enter book title to return: To Kill a Mockingbird

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 4
Title: Harry Potter and the Philosopher's Stone
Author: J.K. Rowling
Availability: Available

Title: To Kill a Mockingbird
Author: Harper Lee
Availability: Available

Library Management System
1. Add Book
2. Borrow Book
3. Return Book
4. Display All Books
5. Exit
Enter your choice: 5