#include <iostream> #include <string> class Book { private: std::string title = "标题待定"; std::string author = "张三"; int pages = 100; double price = 10.0; public: // Getter and Setter std::string getTitle() const { return title; } void setTitle(const std::string& t) { title = t; } std::string getAuthor() const { return author; } void setAuthor(const std::string& a) { author = a; } int getPages() const { return pages; } void setPages(int p) { pages = p; } double getPrice() const { return price; } void setPrice(double pr) { price = pr; } // Operator overloading Book operator+(const Book& other) const { return Book("标题待定", "无名氏", this->pages + other.pages, this->price + other.price); } Book& operator+=(double increment) { this->price += increment; return *this; } Book operator-(const Book& other) const { return Book("标题待定", "无名氏", this->pages - other.pages, this->price - other.price); } }; Book::Book(const std::string& t, const std::string& a, int p, double pr) : title(t), author(a), pages(p), price(pr) {} int main() { Book book1("C++ Primer", "Stanley B. Lippman", 1000, 50.0); Book book2("Effective C++", "Scott Meyers", 300, 30.0); Book sum = book1 + book2; std::cout << "Sum: " << sum.getTitle() << ", " << sum.getAuthor() << ", " << sum.getPages() << " pages, $" << sum.getPrice() << std::endl; book1 += 5.0; std::cout << "Book1 after +=: $" << book1.getPrice() << std::endl; Book diff = book1 - book2; std::cout << "Difference: " << diff.getTitle() << ", " << diff.getAuthor() << ", " << diff.getPages() << " pages, $" << diff.getPrice() << std::endl; return 0; }修改代码

以下是您提供的代码的一个改进版本，其中对某些功能进行了优化，并增加了注释以便于理解： ```cpp #include <iostream> #include <string> using namespace std; // 定义书籍类 class Book { private: string title; // 标题 string author; // 作者 int pages; // 页数 double price; // 价格 public: // 构造函数 Book(string t = "标题未设定", string a = "未知", int p = 0, double pr = 0.0) : title(move(t)), author(move(a)), pages(p), price(pr) {} // 获取和设置属性的方法 string getTitle() const { return title; } void setTitle(const string &t) { title = t; } string getAuthor() const { return author; } void setAuthor(const string &a) { author = a; } int getPages() const { return pages; } void setPages(int p) { if (p >= 0) pages = p; } // 确保页数非负 double getPrice() const { return price; } void setPrice(double pr) { if (pr >= 0) price = pr; } // 确保价格非负 // 运算符重载：加法运算符 (+)，返回新书的对象 Book operator+(const Book &other) const { return Book(title + "+" + other.title, "合并版", pages + other.pages, price + other.price); } // 运算符重载：增加运算符 (+=)，更新当前书的价格 Book &operator+=(double increment) { if (increment > 0) price += increment; // 增量需为正数 return *this; } // 运算符重载：减法运算符 (-)，计算两本书之间的差异 Book operator-(const Book &other) const { return Book("差值", "", abs(pages - other.pages), abs(price - other.price)); // 取绝对值避免负数结果 } // 输出信息至控制台 friend ostream &operator<<(ostream &os, const Book &book); // 友元函数声明 }; // 实现友元函数，用于将书籍内容打印出来 ostream &operator<<(ostream &os, const Book &book) { os << "Title: " << book.title << "\n" << "Author: " << book.author << "\n" << "Pages: " << book.pages << "\n" << "Price: $" << book.price; return os; } int main() { // 创建两个初始书籍对象 Book book1("C++ Primer", "Stanley B. Lippman", 1000, 50.0); Book book2("Effective C++", "Scott Meyers", 300, 30.0); cout << "原始 Book1:\n" << book1 << endl; cout << "原始 Book2:\n" << book2 << endl; // 测试加法操作符 + Book sum = book1 + book2; cout << "\nBook1 加上 Book2 的结果:\n" << sum << endl; // 测试自增操作符 += book1 += 5.0; cout << "\nBook1 经过 += 操作后的结果:\n" << book1 << endl; // 测试减法操作符 - Book diff = book1 - book2; cout << "\nBook1 减去 Book2 后的结果(仅展示数值差异):\n" << diff << endl; return 0; } ``` --- ### 改动点说明： 1. **构造函数改进** 提供了默认参数，在创建空对象时更方便；同时使用 `std::move()` 来提升性能。 2. **边界条件检查** 对输入数据（如页面、价格）加入合法性验证，防止出现不合理情况（例如负数的页码或价格）。 3. **输出流重载** 添加了一个全局的 `operator<<` 以简化调试和显示过程，可以直接用 `cout` 打印整个对象的信息。 4. **字符串拼接优化** 当两本图书相加的时候，新的标题采用组合形式而不是固定名称 ("标题待定")，使逻辑更具意义。 ---