周三打卡

题目描述：

设计一个能够模拟餐厅点餐流程的程序，需要实现以下功能：

1. 显示菜单：输出餐厅提供的所有菜品及其价格。
2. 点餐：输入菜品名称和数量，将菜品添加到订单中。
3. 修改订单：输入菜品名称和数量，修改订单中已有的菜品的数量。
4. 删除订单：输入菜品名称，将菜品从订单中删除。
5. 订单总价：计算订单中所有菜品的总价。

设计思路：

为了实现这个点餐程序，我们需要设计以下几个类：

1. MenuItem类：用于储存菜品信息，包括菜品名称和价格等属性，以及一些方法，如获取与设置菜品信息。
2. OrderItem类：用于储存订单项，包括菜品名称、数量和小计等属性，以及一些方法，如计算小计的方法。
3. Order类：用于储存所有的订单项，包括添加订单项、修改订单项、删除订单项、计算订单总价等方法。
4. Menu类：用于显示菜单，接收用户输入，并调用相应的Order类中的方法。

程序流程图：

start --> displayMenu --> getUserChoice --> performAction --> end
                        |               |
                        v               v
                     addOrder         modifyOrder
                        |               |
                        v               v
                   deleteOrder       calculateTotal

代码实现：

#include <bits/stdc++.h>
using namespace std;
class MenuItem {
private:
    string name;
    int price;
public:
    MenuItem(string n, int p) : name(n), price(p) {}
    string getName() { return name; }
    int getPrice() { return price; }
};
class OrderItem {
private:
    MenuItem menuItem;
    int quantity;
public:
    OrderItem(MenuItem mi, int q) : menuItem(mi), quantity(q) {}
    MenuItem getMenuItem() { return menuItem; }
    int getQuantity() { return quantity; }
    void setQuantity(int q) { quantity = q; }
    int getSubtotal() { return menuItem.getPrice() * quantity; }
};
class Order {
private:
    vector<OrderItem> orderItems;
public:
    void addOrder(MenuItem menuItem, int quantity) {
        OrderItem orderItem = OrderItem(menuItem, quantity);
        orderItems.push_back(orderItem);
    }

    void modifyOrder(MenuItem menuItem, int quantity) {
        for (int i = 0; i < orderItems.size(); i++) {
            if (orderItems[i].getMenuItem().getName() == menuItem.getName()) {
                orderItems[i].setQuantity(quantity);
                break;
            }
        }
    }

    void deleteOrder(MenuItem menuItem) {
        for (int i = 0; i < orderItems.size(); i++) {
            if (orderItems[i].getMenuItem().getName() == menuItem.getName()) {
                orderItems.erase(orderItems.begin() + i);
                break;
            }
        }
    }

    int calculateTotal() {
        int total = 0;
        for (OrderItem orderItem : orderItems) {
            total += orderItem.getSubtotal();
        }
        return total;
    }
};
class Menu {
private:
    Order order;
    vector<MenuItem> menuItems = {
        MenuItem("A", 10),
        MenuItem("B", 15),
        MenuItem("C", 20),
        MenuItem("D", 25)
    };
public:
    void displayMenu() {
        cout << "Menu:" << endl;
        for (MenuItem menuItem : menuItems) {
            cout << menuItem.getName() << ": $" << menuItem.getPrice() << endl;
        }
        cout << endl;
    }

    string getMenuItemName() {
        string name;
        cout << "Enter the name of the item: ";
        getline(cin >> ws, name);
        return name;
    }

    int getQuantity() {
        int quantity;
        cout << "Enter the quantity of the item: ";
        cin >> quantity;
        return quantity;
    }

    int getUserChoice() {
        int choice;
        cout << "Enter your choice: ";
        cin >> choice;
        cout << endl;
        return choice;
    }

    void performAction(int choice) {
        string menuItemName;
        int quantity, total;

        switch (choice) {
            case 1:
                displayMenu();
                break;
            case 2:
                menuItemName = getMenuItemName();
                quantity = getQuantity();
                for (MenuItem menuItem : menuItems) {
                    if (menuItem.getName() == menuItemName) {
                        order.addOrder(menuItem, quantity);
                        cout << quantity << " " << menuItemName << "(s) have been added to the order." << endl << endl;
                        return;
                    }
                }
                cout << "Invalid item name. Please try again." << endl << endl;
                break;
            case 3:
                menuItemName = getMenuItemName();
                quantity = getQuantity();
                for (MenuItem menuItem : menuItems) {
                    if (menuItem.getName() == menuItemName) {
                        order.modifyOrder(menuItem, quantity);
                        cout << menuItemName << "(s) quantity has been modified to " << quantity << "." << endl << endl;
                        return;
                    }
                }
                cout << "Invalid item name. Please try again." << endl << endl;
                break;
            case 4:
                menuItemName = getMenuItemName();
                for (MenuItem menuItem : menuItems) {
                    if (menuItem.getName() == menuItemName) {
                        order.deleteOrder(menuItem);
                        cout << menuItemName << "(s) have been removed from the order." << endl << endl;
                        return;
                    }
                }
                cout << "Invalid item name. Please try again." << endl << endl;
                break;
            case 5:
                total = order.calculateTotal();
                cout << "Total: $" << total << endl << endl;
                break;
            default:
                cout << "Invalid choice. Please try again." << endl << endl;
        }
    }
};
int main() {
    Menu menu = Menu();
    int choice;

    while (true) {
        cout << "1. Display menu" << endl;
        cout << "2. Add item to order" << endl;
        cout << "3. Modify item in order" << endl;
        cout << "4. Delete item from order" << endl;
        cout << "5. Calculate order total" << endl;
        choice = menu.getUserChoice();
        menu.performAction(choice);
    }

    return 0;
}