Code kata for a order list

ShoppingList.cpp

#include <iostream>
#include <cstdint>
#include <vector>
#include <limits>
#include <cstring>
#include <sstream>
#include <chrono>
#include <set>
#include <stack>
#include <map>
#include <algorithm>

using namespace std;

struct OrderItem {
    string name;
    double price;
    int quantity;

    double calculateTotalPrice() const {
        return price * quantity;
    }

    bool operator<(const OrderItem& other) const {
        return calculateTotalPrice() < other.calculateTotalPrice();
    }

    friend ostream& operator<<(ostream& os, const OrderItem& item) {
        os << item.name << " " << item.calculateTotalPrice();
        return os;
    }
};

struct Order {
    vector<OrderItem> orderItems;

    double calculateTotalPrice() const {
        double total = 0.0;

        for (const OrderItem& item : orderItems) {
            total += item.calculateTotalPrice();
        }

        return total;
    }

    void sorted() {
        sort(orderItems.rbegin(), orderItems.rend());
    }

    friend ostream& operator<<(ostream& os, const Order& order) {
        os << "The total sum is: " << order.calculateTotalPrice() << " lv." << endl;

        for (const OrderItem& item : order.orderItems) {
            os << item << endl;
        }

        return os;
    }
};

int main() {
    int64_t numberOfShoppingItems;
    cin >> numberOfShoppingItems;
    Order order;

    for (int64_t shoppingItemId = 0; shoppingItemId < numberOfShoppingItems; shoppingItemId++) {
        OrderItem item;

        cin >> item.name >> item.price >> item.quantity;

        order.orderItems.push_back(item);
    }

    order.sorted();

    cout << order;

    return 0;
}