功能：屏幕上出现一个界面，让顾客或输入商品名称，或商品型号，或选择列表进而输入 商品编号都可以，如查到所选商品，则列出商品编号、商品名称、商品型号、商品价格、商品产地、库存数量和已订购数量；然后给出选购流程：所选商品编号—列出对应商品的信息—要求顾客输入邮寄地址信息—确认订购，是否继续选购其它商品，列出所有选订商品，再次确认订购。建立两个文件，分别存放商品信息与订购信息。 分步实施： 1、 初步完成总体设计，搭好框架，确定人机对话的界面，确定函数个数； 2、完成最低要求：建立一个小系统，包括10种产品能供顾客选择。 3、进一步要求：完成全部功能的系统

好的，以下是一个实现了您所需功能的C++商品订购系统的代码示例：

#include <iostream>
#include <fstream>
#include <string>
#include <vector>

using namespace std;

// 商品类
class Product {
public:
    Product(string id, string name, string model, int price, string origin, int stock, int ordered) {
        this->id = id;
        this->name = name;
        this->model = model;
        this->price = price;
        this->origin = origin;
        this->stock = stock;
        this->ordered = ordered;
    }

    string getId() {
        return id;
    }

    string getName() {
        return name;
    }

    string getModel() {
        return model;
    }

    int getPrice() {
        return price;
    }

    string getOrigin() {
        return origin;
    }

    int getStock() {
        return stock;
    }

    int getOrdered() {
        return ordered;
    }

    void setStock(int stock) {
        this->stock = stock;
    }

    void setOrdered(int ordered) {
        this->ordered = ordered;
    }

private:
    string id;
    string name;
    string model;
    int price;
    string origin;
    int stock;
    int ordered;
};

// 商品清单类
class ProductList {
public:
    void loadProducts(string filename) { // 从文件中加载商品信息
        ifstream infile(filename);
        string line;
        while (getline(infile, line)) {
            string id, name, model, origin;
            int price, stock, ordered;
            stringstream ss(line);
            ss >> id >> name >> model >> price >> origin >> stock >> ordered;
            Product product(id, name, model, price, origin, stock, ordered);
            products.push_back(product);
        }
        infile.close();
    }

    void saveProducts(string filename) { // 将商品信息保存到文件中
        ofstream outfile(filename);
        for (int i = 0; i < products.size(); i++) {
            Product product = products[i];
            outfile << product.getId() << " " << product.getName() << " " << product.getModel() << " " << product.getPrice() << " " << product.getOrigin() << " " << product.getStock() << " " << product.getOrdered() << endl;
        }
        outfile.close();
    }

    int getProductCount() {
        return products.size();
    }

    Product getProduct(int index) {
        return products[index];
    }

    vector<Product> findProducts(string keyword) { // 根据关键字查找商品
        vector<Product> result;
        for (int i = 0; i < products.size(); i++) {
            Product product = products[i];
            if (product.getId() == keyword || product.getName() == keyword || product.getModel() == keyword) {
                result.push_back(product);
            }
        }
        return result;
    }

private:
    vector<Product> products;
};

// 订单类
class Order {
public:
    Order(Product product, int quantity, string address) {
        this->product = product;
        this->quantity = quantity;
        this->address = address;
    }

    Product getProduct() {
        return product;
    }

    int getQuantity() {
        return quantity;
    }

    string getAddress() {
        return address;
    }

    int getTotalPrice() {
        return product.getPrice() * quantity;
    }

private:
    Product product;
    int quantity;
    string address;
};

// 订单列表类
class OrderList {
public:
    void loadOrders(string filename) { // 从文件中加载订单信息
        ifstream infile(filename);
        string line;
        while (getline(infile, line)) {
            string productId, address;
            int quantity;
            stringstream ss(line);
            ss >> productId >> quantity >> address;
            Product product = productMap[productId];
            Order order(product, quantity, address);
            orders.push_back(order);
        }
        infile.close();
    }

    void saveOrders(string filename) { // 将订单信息保存到文件中
        ofstream outfile(filename);
        for (int i = 0; i < orders.size(); i++) {
            Order order = orders[i];
            outfile << order.getProduct().getId() << " " << order.getQuantity() << " " << order.getAddress() << endl;
        }
        outfile.close();
    }

    void addOrder(Order order) {
        orders.push_back(order);
        Product product = order.getProduct();
        product.setStock(product.getStock() - order.getQuantity());
        product.setOrdered(product.getOrdered() + order.getQuantity());
    }

    int getOrderCount() {
        return orders.size();
    }

    Order getOrder(int index) {
        return orders[index];
    }

    int getTotalPrice() {
        int totalPrice = 0;
        for (int i = 0; i < orders.size(); i++) {
            totalPrice += orders[i].getTotalPrice();
        }
        return totalPrice;
    }

private:
    vector<Order> orders;
    map<string, Product> productMap;
};

// 主函数
int main() {
    // 创建商品清单
    ProductList productList;
    productList.loadProducts("products.txt");

    // 创建订单列表
    OrderList orderList;
    orderList.loadOrders("orders.txt");

    // 显示主菜单
    while (true) {
        cout << "请选择操作：" << endl;
        cout << "1. 查找商品" << endl;
        cout << "2. 查看购物车" << endl;
        cout << "3. 结算购物车" << endl;
        cout << "4. 退出程序" << endl;
        int choice;
        cin >> choice;
        if (choice == 1) {
            // 查找商品
            cout << "请输入商品关键字：";
            string keyword;
            cin >> keyword;
            vector<Product> products = productList.findProducts(keyword);
            if (products.size() == 0) {
                cout << "没有找到匹配的商品！" << endl;
            } else if (products.size() == 1) {
                Product product = products[0];
                cout << "商品编号：" << product.getId() << endl;
                cout << "商品名称：" << product.getName() << endl;
                cout << "商品型号：" << product.getModel() << endl;
                cout << "商品价格：" << product.getPrice() << "元" << endl;
                cout << "商品产地：" << product.getOrigin() << endl;
                cout << "库存数量：" << product.getStock() << endl;
                cout << "已订购数量：" << product.getOrdered() << endl;
                cout << endl;
                // 购买商品
                cout << "请输入购买数量：";
                int quantity;
                cin >> quantity;
                if (quantity <= 0) {
                    cout << "购买数量必须大于0！" << endl;
                } else if (quantity > product.getStock()) {
                    cout << "库存不足！" << endl;
                } else {
                    cout << "请输入邮寄地址：";
                    string address;
                    cin >> address;
                    Order order(product, quantity, address);
                    orderList.addOrder(order);
                    cout << "已成功加入购物车！" << endl;
                }
            } else {
                cout << "找到以下匹配的商品：" << endl;
                for (int i = 0; i < products.size(); i++) {
                    Product product = products[i];
                    cout << i + 1 << ". 商品编号：" << product.getId() << "，商品名称：" << product.getName() << "，商品型号：" << product.getModel() << "，商品价格：" << product.getPrice() << "元" << endl;
                }
                cout << "请选择商品编号：";
                int index;
                cin >> index;
                if (index <= 0 || index > products.size()) {
                    cout << "无效的商品编号！" << endl;
                } else {
                    Product product = products[index - 1];
                    cout << "商品编号：" << product.getId() << endl;
                    cout << "商品名称：" << product.getName() << endl;
                    cout << "商品型号：" << product.getModel() << endl;
                    cout << "商品价格：" << product.getPrice() << "元" << endl;
                    cout << "商品产地：" << product.getOrigin() << endl;
                    cout << "库存数量：" << product.getStock() << endl;
                    cout << "已订购数量：" << product.getOrdered() << endl;
                    cout << endl;
                    // 购买商品
                    cout << "请输入购买数量：";
                    int quantity;
                    cin >> quantity;
                    if (quantity <= 0) {
                        cout << "购买数量必须大于0！" << endl;
                    } else if (quantity > product.getStock()) {
                        cout << "库存不足！" << endl;
                    } else {
                        cout << "请输入邮寄地址：";
                        string address;
                        cin >> address;
                        Order order(product, quantity, address);
                        orderList.addOrder(order);
                        cout << "已成功加入购物车！" << endl;
                    }
                }
            }
        } else if (choice == 2) {
            // 查看购物车
            cout << "您的购物车：" << endl;
            for (int i = 0; i < orderList.getOrderCount(); i++) {
                Order order = orderList.getOrder(i);
                cout << i + 1 << ". 商品名称：" << order.getProduct().getName() << "，购买数量：" << order.getQuantity() << "，邮寄地址：" << order.getAddress() << "，小计：" << order.getTotalPrice() << "元" << endl;
            }
            cout << "总金额：" << orderList.getTotalPrice() << "元" << endl;
        } else if (choice == 3) {
            // 结算购物车
            cout << "您的购物车：" << endl;
            for (int i = 0; i < orderList.getOrderCount(); i++) {
                Order order = orderList.getOrder(i);
                cout << i + 1 << ". 商品名称：" << order.getProduct().getName() << "，购买数量：" << order.getQuantity() << "，邮寄地址：" << order.getAddress() << "，小计：" << order.getTotalPrice() << "元" << endl;
            }
            cout << "总金额：" << orderList.getTotalPrice() << "元" << endl;
            cout << "是否确认结算？（Y/N）";
            char confirm;
            cin >> confirm;
            if (confirm == 'Y' || confirm == 'y') {
                // 更新商品清单和订单列表
                productList.saveProducts("products.txt");
                orderList.saveOrders("orders.txt");
                // 显示结算成功信息
                cout << "结算成功！" << endl;
                cout << "已将商品邮寄至您的地址。" << endl;
                cout << "谢谢光临！" << endl;
                break;
            }
        } else if (choice == 4) {
            // 退出程序
            break;
        } else {
            // 无效操作
            cout << "无效的操作！" << endl;
        }
        cout << endl;
    }

    return 0;
}

以上代码实现了一个完整的商品订购系统，可以根据用户的选择查找商品、购买商品、查看购物车、结算购物车等。商品信息和订单信息分别保存在两个文件中，程序启动时从文件中加载商品信息和订单信息，并在结算购物车时将更新后的商品信息和订单信息保存回文件中。请注意，此代码示例仅供参考，实际应用中可能需要更复杂的功能和更严格的错误处理。