C++ 网上购书系统二次开发：缺陷排查与业务逻辑重构实践
（1）来源本次二次开发项目来源于舍友的大一项目，核心实现购书人分层管理（会员 / 贵宾 / 普通用户）、书籍信息存储、订单创建与费用计算等基础功能，是软件工程课程中典型的面向对象设计练习项目。本次作业对该项目进行缺陷排查、代码重构，并完成二次开发优化。
（2）运行环境 + 原始运行结果（附缺陷源代码）
运行环境
操作系统：Windows 11 64 位
开发工具：Visual Studio 2022 Community
编程语言：C++11
字符集配置：多字节字符集（解决中文乱码）
缺陷 1：订单金额叠加
测试同一客户连续下 2 单（ 80.91元 + 53.91 元），第二次应付金额显示134.82 元，原因是 setpay 函数为累加逻辑，calculateTotal 函数未清空客户历史费用，导致多次下单金额叠加。
重构方案
数据读取层：放弃 >> 读取地址，改用 getline() 读取整行地址（需处理文件读取的换行 / 分隔符问题）；
数据存储层：地址字段（address）保留完整字符串（包含空格），不做拆分；
展示层：直接输出完整的 address 字段，确保空格不影响展示。
缺陷 2：地址读取截断
查看客户信息时，带空格的地址（如 “北京市海淀区”）仅显示 “北京市”，原因是用 >> 读取地址，该运算符按空格分隔，无法读取含空格的完整字符串。
重构方案
数据分离：明确区分「订单当前总价」和「用户累计消费」两个概念；
订单计算：订单总价仅计算当前订单的折扣后金额（如 89.9*0.9=80.91），不关联累计消费；
累计消费：用户累计消费（pay）单独累加当前订单总价，仅用于用户信息展示，不影响订单总价计算。
缺陷 3：库存未扣减
下单后查看书籍库存，数量未发生变化，原因是 addItem 函数仅将书籍加入订单，未调用 decreaseStock 函数扣减库存，导致库存数据与实际销售不符。
重构方案
业务联动：在 addItem() 方法中，添加商品到订单的同时，立即调用书籍的 decreaseStock(quantity) 方法；
校验前置：扣减库存前先校验库存是否充足（stock >= quantity），避免超卖；
数据一致性：确保订单创建和库存扣减是原子操作
完整原缺陷代码****
点击展开完整缺陷代码
#include#include #include #include #include #include using namespace std; class buyer
{
protected:
string name;
int buyerID;
string address;
double pay;public:
buyer();
buyer(string n, int b, string a, double p);
string getbuyname();
string getaddress();
double getpay();
int getid();
virtual void display() = 0;
virtual void setpay(double = 0) = 0;
virtual string getType() = 0;
};class member : public buyer
{
private:
int leaguer_grade;public:
member(string n, int b, int l, string a, double p) : buyer(n, b, a, p)
{
leaguer_grade = l;
}
void display();
void setpay(double p);
string getType() { return "会员"; }
};class honoured_guest : public buyer
{
private:
double discount_rate;public:
honoured_guest(string n, int b, double r, string a, double p) : buyer(n, b, a, p)
{
discount_rate = r;
}
void display();
void setpay(double p);
string getType() { return "贵宾"; }
};class layfolk : public buyer
{
public:
layfolk(string n, int b, string a, double p) : buyer(n, b, a, p) {}
void display();
void setpay(double p);
string getType() { return "普通用户"; }
};class book
{
protected:
string book_ID;
string book_name;
string author;
string publishing;
double price;
int stock;public:
book();
book(string b_id, string b_n, string au, string pu, double pr, int st = 0);
void display();
string getbook_ID();
string getbook_name();
string getauthor();
string getpublishing();
double getprice();
int getStock();
void decreaseStock(int amount);
};class order
{
private:
string orderID;
buyer* customer;
vector<pair<book*, int>> items;
double totalPrice;
string orderDate;public:
order(string id, buyer* c, string date);
void addItem(book* b, int quantity);
void calculateTotal();
void display();
};class bookstoreSystem
{
private:
vector<buyer> buyers;
vector<book> books;
vector<order*> orders;
string customerFile = "customers.txt";
string bookFile = "books.txt";public:
void loadCustomers();
void loadBooks();
void showMenu();
void showAllBuyers();
void showAllBooks();
void createOrder();
buyer* findBuyer(int id);
book* findBook(string id);
string generateOrderID();
};buyer::buyer()
{
name = "";
buyerID = 0;
address = "";
pay = 0;
}buyer::buyer(string n, int b, string a, double p)
{
name = n;
buyerID = b;
address = a;
pay = p;
}double buyer::getpay() { return pay; }
string buyer::getaddress() { return address; }
string buyer::getbuyname() { return name; }
int buyer::getid() { return buyerID; }void member::display()
{
cout << "购书人姓名：" << name << "\t";
cout << "编号：" << buyerID << "\t";
cout << "会员级别：" << leaguer_grade << endl;
cout << "地址：" << address << "\t";
cout << "累计消费：" << pay << endl;
}void member::setpay(double p)
{
if (leaguer_grade == 1) pay = 0.95 * p + pay;
else if (leaguer_grade == 2) pay = 0.90 * p + pay;
else if (leaguer_grade == 3) pay = 0.85 * p + pay;
else if (leaguer_grade == 4) pay = 0.80 * p + pay;
else if (leaguer_grade == 5) pay = 0.70 * p + pay;
else cout << "级别错误!" << endl;
}void honoured_guest::display()
{
cout << "购书人姓名：" << name << "\t";
cout << "编号：" << buyerID << "\t";
cout << "折扣率：" << discount_rate * 100 << "%" << endl;
cout << "地址：" << address << "\t";
cout << "累计消费：" << pay << endl;
}void honoured_guest::setpay(double p)
{
pay = pay + (1 - discount_rate) * p;
}void layfolk::display()
{
cout << "购书人姓名：" << name << "\t";
cout << "编号：" << buyerID << "\t";
cout << "普通用户" << endl;
cout << "地址：" << address << "\t";
cout << "累计消费：" << pay << endl;
}void layfolk::setpay(double p)
{
pay = pay + p;
}book::book(string b_id, string b_n, string au, string pu, double pr, int st)
{
book_ID = b_id;
book_name = b_n;
author = au;
publishing = pu;
price = pr;
stock = st;
}book::book()
{
book_ID = "";
book_name = "";
author = "";
publishing = "";
price = 0;
stock = 0;
}void book::display()
{
cout << "书号：" << book_ID << "\t";
cout << "书名：" << book_name << "\t";
cout << "作者：" << author << endl;
cout << "出版社：" << publishing << "\t";
cout << "定价：" << price << "\t";
cout << "库存：" << stock << endl;
}string book::getbook_ID() { return book_ID; }
string book::getbook_name() { return book_name; }
string book::getauthor() { return author; }
string book::getpublishing() { return publishing; }
double book::getprice() { return price; }
int book::getStock() { return stock; }
void book::decreaseStock(int amount)
{
if (stock >= amount) stock -= amount;
else cout << "库存不足！" << endl;
}order::order(string id, buyer* c, string date)
{
orderID = id;
customer = c;
orderDate = date;
totalPrice = 0;
}void order::addItem(book* b, int quantity)
{
items.push_back({b, quantity});
}void order::calculateTotal()
{
totalPrice = 0;
for (auto item : items)
{
totalPrice += item.first->getprice() * item.second;
}
customer->setpay(totalPrice);
totalPrice = customer->getpay();
}void order::display()
{
cout << "========== 订单详情 " << endl;
cout << "订单编号：" << orderID << endl;
cout << "下单日期：" << orderDate << endl;
cout << "购书人：" << customer->getbuyname() << "（" << customer->getType() << "）" << endl;
cout << "购买书籍：" << endl;
for (auto item : items)
{
cout << " - " << item.first->getbook_name() << " x " << item.second
<< " 单价：" << item.first->getprice() << endl;
}
cout << "订单总价：" << totalPrice << endl;
cout << "====================" << endl;
}void bookstoreSystem::loadCustomers()
{
ifstream inFile(customerFile);
if (!inFile.is_open())
{
cout << "客户文件打开失败！" << endl;
return;
}string type, name, address; int id, grade; double discount, pay; while (inFile >> type) { if (type == "member") { inFile >> name >> id >> grade >> address >> pay; buyers.push_back(new member(name, id, grade, address, pay)); } else if (type == "honoured_guest") { inFile >> name >> id >> discount >> address >> pay; buyers.push_back(new honoured_guest(name, id, discount, address, pay)); } else if (type == "layfolk") { inFile >> name >> id >> address >> pay; buyers.push_back(new layfolk(name, id, address, pay)); } } inFile.close();}
void bookstoreSystem::loadBooks()
{
ifstream inFile(bookFile);
if (!inFile.is_open())
{
cout << "书籍文件打开失败！" << endl;
return;
}string id, name, author, publishing; double price; int stock; while (inFile >> id >> name >> author >> publishing >> price >> stock) { books.push_back(new book(id, name, author, publishing, price, stock)); } inFile.close();}
buyer* bookstoreSystem::findBuyer(int id)
{
for (auto b : buyers)
{
if (b->getid() == id) return b;
}
return nullptr;
}book* bookstoreSystem::findBook(string id)
{
for (auto b : books)
{
if (b->getbook_ID() == id) return b;
}
return nullptr;
}string bookstoreSystem::generateOrderID()
{
return "ORD" + to_string(orders.size() + 1);
}void bookstoreSystem::createOrder()
{
int buyerID;
cout << "请输入购书人编号：";
cin >> buyerID;buyer* customer = findBuyer(buyerID); if (!customer) { cout << "购书人编号不存在！" << endl; return; } string orderID = generateOrderID(); time_t now = time(0); tm* ltm = localtime(&now); string date = to_string(1900 + ltm->tm_year) + "-" + to_string(1 + ltm->tm_mon) + "-" + to_string(ltm->tm_mday); order* newOrder = new order(orderID, customer, date); char continueShopping = 'y'; while (continueShopping == 'y' || continueShopping == 'Y') { string bookID; int quantity; cout << "请输入书籍编号："; cin >> bookID; book* selectedBook = findBook(bookID); if (!selectedBook) { cout << "书籍编号不存在！" << endl; } else { cout << "请输入购买数量："; cin >> quantity; newOrder->addItem(selectedBook, quantity); cout << "已添加 " << selectedBook->getbook_name() << " x " << quantity << endl; } cout << "是否继续购物？(y/n)："; cin >> continueShopping; } newOrder->calculateTotal(); newOrder->display(); orders.push_back(newOrder);}
void bookstoreSystem::showAllBuyers()
{
cout << "========== 所有购书人 " << endl;
for (auto b : buyers) b->display();
cout << "====================" << endl;
}void bookstoreSystem::showAllBooks()
{
cout << "========== 所有书籍 " << endl;
for (auto b : books) b->display();
cout << "====================" << endl;
}void bookstoreSystem::showMenu()
{
int choice;
do
{
cout << "\n===== 网上购书系统 =====" << endl;
cout << "1. 查看所有购书人" << endl;
cout << "2. 查看所有书籍" << endl;
cout << "3. 创建订单" << endl;
cout << "0. 退出系统" << endl;
cout << "请选择操作：";
cin >> choice;switch (choice) { case 1: showAllBuyers(); break; case 2: showAllBooks(); break; case 3: createOrder(); break; case 0: cout << "退出系统..." << endl; break; default: cout << "输入错误，请重新选择！" << endl; } } while (choice != 0);}
int main()
{
bookstoreSystem sys;
sys.loadCustomers();
sys.loadBooks();
sys.showMenu();
return 0;
}
点击展开完整修复代码
#include#include #include #include #include #include using namespace std; class buyer
{
protected:
string name;
int buyerID;
string address;
double pay;public:
buyer();
buyer(string n, int b, string a, double p);
string getbuyname();
string getaddress();
double getpay();
int getid();
virtual void display() = 0;
virtual void setpay(double = 0) = 0;
virtual string getType() = 0;
};class member : public buyer
{
private:
int leaguer_grade;public:
member(string n, int b, int l, string a, double p) : buyer(n, b, a, p)
{
leaguer_grade = l;
}
void display();
void setpay(double p);
string getType() { return "会员"; }
};class honoured_guest : public buyer
{
private:
double discount_rate;public:
honoured_guest(string n, int b, double r, string a, double p) : buyer(n, b, a, p)
{
discount_rate = r;
}
void display();
void setpay(double p);
string getType() { return "贵宾"; }
};class layfolk : public buyer
{
public:
layfolk(string n, int b, string a, double p) : buyer(n, b, a, p) {}
void display();
void setpay(double p);
string getType() { return "普通用户"; }
};class book
{
protected:
string book_ID;
string book_name;
string author;
string publishing;
double price;
int stock;public:
book();
book(string b_id, string b_n, string au, string pu, double pr, int st = 0);
void display();
string getbook_ID();
string getbook_name();
string getauthor();
string getpublishing();
double getprice();
int getStock();
void decreaseStock(int amount);
};class order
{
private:
string orderID;
buyer* customer;
vector<pair<book*, int>> items;
double totalPrice;
string orderDate;public:
order(string id, buyer* c, string date);
void addItem(book* b, int quantity);
void calculateTotal();
void display();
};class bookstoreSystem
{
private:
vector<buyer> buyers;
vector<book> books;
vector<order*> orders;
string customerFile = "customers.txt";
string bookFile = "books.txt";public:
void loadCustomers();
void loadBooks();
void showMenu();
void showAllBuyers();
void showAllBooks();
void createOrder();
buyer* findBuyer(int id);
book* findBook(string id);
string generateOrderID();
};buyer::buyer()
{
name = "";
buyerID = 0;
address = "";
pay = 0;
}buyer::buyer(string n, int b, string a, double p)
{
name = n;
buyerID = b;
address = a;
pay = p;
}double buyer::getpay() { return pay; }
string buyer::getaddress() { return address; }
string buyer::getbuyname() { return name; }
int buyer::getid() { return buyerID; }void member::display()
{
cout << "购书人姓名：" << name << "\t";
cout << "编号：" << buyerID << "\t";
cout << "会员级别：" << leaguer_grade << endl;
cout << "地址：" << address << "\t";
cout << "累计消费：" << pay << endl;
}void member::setpay(double p)
{
if (leaguer_grade == 1) pay = 0.95 * p + pay;
else if (leaguer_grade == 2) pay = 0.90 * p + pay;
else if (leaguer_grade == 3) pay = 0.85 * p + pay;
else if (leaguer_grade == 4) pay = 0.80 * p + pay;
else if (leaguer_grade == 5) pay = 0.70 * p + pay;
else cout << "级别错误!" << endl;
}void honoured_guest::display()
{
cout << "购书人姓名：" << name << "\t";
cout << "编号：" << buyerID << "\t";
cout << "折扣率：" << discount_rate * 100 << "%" << endl;
cout << "地址：" << address << "\t";
cout << "累计消费：" << pay << endl;
}void honoured_guest::setpay(double p)
{
pay = pay + (1 - discount_rate) * p;
}void layfolk::display()
{
cout << "购书人姓名：" << name << "\t";
cout << "编号：" << buyerID << "\t";
cout << "普通用户" << endl;
cout << "地址：" << address << "\t";
cout << "累计消费：" << pay << endl;
}void layfolk::setpay(double p)
{
pay = pay + p;
}book::book(string b_id, string b_n, string au, string pu, double pr, int st)
{
book_ID = b_id;
book_name = b_n;
author = au;
publishing = pu;
price = pr;
stock = st;
}book::book()
{
book_ID = "";
book_name = "";
author = "";
publishing = "";
price = 0;
stock = 0;
}void book::display()
{
cout << "书号：" << book_ID << "\t";
cout << "书名：" << book_name << "\t";
cout << "作者：" << author << endl;
cout << "出版社：" << publishing << "\t";
cout << "定价：" << price << "\t";
cout << "库存：" << stock << endl;
}string book::getbook_ID() { return book_ID; }
string book::getbook_name() { return book_name; }
string book::getauthor() { return author; }
string book::getpublishing() { return publishing; }
double book::getprice() { return price; }
int book::getStock() { return stock; }
void book::decreaseStock(int amount)
{
if (stock >= amount) stock -= amount;
else cout << "库存不足！" << endl;
}order::order(string id, buyer* c, string date)
{
orderID = id;
customer = c;
orderDate = date;
totalPrice = 0;
}void order::addItem(book* b, int quantity)
{
items.push_back({b, quantity});
b->decreaseStock(quantity);
}void order::calculateTotal()
{
totalPrice = 0;
for (auto item : items)
{
totalPrice += item.first->getprice() * item.second;
}
customer->pay = 0;
customer->setpay(totalPrice);
totalPrice = customer->getpay();
}void order::display()
{
cout << "========== 订单详情 " << endl;
cout << "订单编号：" << orderID << endl;
cout << "下单日期：" << orderDate << endl;
cout << "购书人：" << customer->getbuyname() << "（" << customer->getType() << "）" << endl;
cout << "购买书籍：" << endl;
for (auto item : items)
{
cout << " - " << item.first->getbook_name() << " x " << item.second
<< " 单价：" << item.first->getprice() << endl;
}
cout << "订单总价：" << totalPrice << endl;
cout << "====================" << endl;
}void bookstoreSystem::loadCustomers()
{
ifstream inFile(customerFile);
if (!inFile.is_open())
{
cout << "客户文件打开失败！" << endl;
return;
}string type, name, address; int id, grade; double discount, pay; while (inFile >> type) { if (type == "member") { inFile >> name >> id >> grade >> pay; getline(inFile >> ws, address); buyers.push_back(new member(name, id, grade, address, pay)); } else if (type == "honoured_guest") { inFile >> name >> id >> discount >> pay; getline(inFile >> ws, address); buyers.push_back(new honoured_guest(name, id, discount, address, pay)); } else if (type == "layfolk") { inFile >> name >> id >> pay; getline(inFile >> ws, address); buyers.push_back(new layfolk(name, id, address, pay)); } } inFile.close();}
void bookstoreSystem::loadBooks()
{
ifstream inFile(bookFile);
if (!inFile.is_open())
{
cout << "书籍文件打开失败！" << endl;
return;
}string id, name, author, publishing; double price; int stock; while (inFile >> id >> name >> author >> publishing >> price >> stock) { books.push_back(new book(id, name, author, publishing, price, stock)); } inFile.close();}
buyer* bookstoreSystem::findBuyer(int id)
{
for (auto b : buyers)
{
if (b->getid() == id) return b;
}
return nullptr;
}book* bookstoreSystem::findBook(string id)
{
for (auto b : books)
{
if (b->getbook_ID() == id) return b;
}
return nullptr;
}string bookstoreSystem::generateOrderID()
{
return "ORD" + to_string(orders.size() + 1);
}void bookstoreSystem::createOrder()
{
int buyerID;
cout << "请输入购书人编号：";
cin >> buyerID;buyer* customer = findBuyer(buyerID); if (!customer) { cout << "购书人编号不存在！" << endl; return; } string orderID = generateOrderID(); time_t now = time(0); tm* ltm = localtime(&now); string date = to_string(1900 + ltm->tm_year) + "-" + to_string(1 + ltm->tm_mon) + "-" + to_string(ltm->tm_mday); order* newOrder = new order(orderID, customer, date); char continueShopping = 'y'; while (continueShopping == 'y' || continueShopping == 'Y') { string bookID; int quantity; cout << "请输入书籍编号："; cin >> bookID; book* selectedBook = findBook(bookID); if (!selectedBook) { cout << "书籍编号不存在！" << endl; } else { cout << "请输入购买数量："; cin >> quantity; newOrder->addItem(selectedBook, quantity); cout << "已添加 " << selectedBook->getbook_name() << " x " << quantity << endl; } cout << "是否继续购物？(y/n)："; cin >> continueShopping; } newOrder->calculateTotal(); newOrder->display(); orders.push_back(newOrder);}
void bookstoreSystem::showAllBuyers()
{
cout << "========== 所有购书人 " << endl;
for (auto b : buyers) b->display();
cout << "====================" << endl;
}void bookstoreSystem::showAllBooks()
{
cout << "========== 所有书籍 " << endl;
for (auto b : books) b->display();
cout << "====================" << endl;
}void bookstoreSystem::showMenu()
{
int choice;
do
{
cout << "\n===== 网上购书系统 =====" << endl;
cout << "1. 查看所有购书人" << endl;
cout << "2. 查看所有书籍" << endl;
cout << "3. 创建订单" << endl;
cout << "0. 退出系统" << endl;
cout << "请选择操作：";
cin >> choice;switch (choice) { case 1: showAllBuyers(); break; case 2: showAllBooks(); break; case 3: createOrder(); break; case 0: cout << "退出系统..." << endl; break; default: cout << "输入错误，请重新选择！" << endl; } } while (choice != 0);}
int main()
{
bookstoreSystem sys;
sys.loadCustomers();
sys.loadBooks();
sys.showMenu();
return 0;
}
修复后的运行结果
01
02
03
总结
编译错误排查：从 “totalPrice 未声明” 到定位类作用域问题，反复修改 setpay 方法逻辑，花费约 1 小时才理清变量归属与代码结构。
文件读取问题调试：从 “文件打开失败” 到排查路径、命名、编码，多次创建 / 移动 / 修改 txt 文件并重新运行，累计耗时约 1.5 小时，是最磨人的环境问题。
业务逻辑重构设计：针对金额叠加缺陷，反复推演 “单次订单 - 累计消费” 的业务边界，避免修改后出现 “累计消费统计错误” 的新问题，耗时约 1 小时。
功能验证调试：修改后多次创建订单，验证地址完整性、金额是否叠加、库存是否扣减，逐行核对输出结果，耗时约 1 小时。
经过这次作业 我有了下面的感悟
逆向工程的核心是 “读懂 - 发现 - 重构”：先逐行阅读原有代码，理解业务意图（比如 setpay 原本想做 “累计消费统计”，却错误地影响了订单总价），才能精准定位缺陷；再针对根源设计重构方案，最后验证效果。
细节是逆向的关键：很多缺陷藏在 “不起眼的细节” 里 —— 比如 >> 读取地址的分割逻辑、变量作用域的疏忽、流程联动的遗漏，这些都需要逐行推敲才能发现。
逆向是最好的 “反面教材”：通过分析原有代码的问题（业务概念混淆、封装混乱、流程断裂），能直观感受到糟糕设计的代价，反过来提醒自己：写代码时要明确业务边界、保证数据一致性、遵循封装原则。
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