帮我写mainprogram

编写 `MainProgram` 类需要实现与用户的交互，并处理各种操作请求。以下是一个示例实现，涵盖了任务要求的所有功能：

### MainProgram.java

import java.io.*;
import java.util.Scanner;

public class MainProgram {
    private static Scanner scanner = new Scanner(System.in);
    private static SortedLinkedList<Ticket> tickets;
    private static SortedLinkedList<Customer> customers;

    public static void main(String[] args) {
        // 初始化数据
        initializeData();

        // 主菜单循环
        while (true) {
            displayMenu();
            char choice = getChoice();
            processChoice(choice);

            if (choice == 'f') break;
        }
    }

    private static void initializeData() {
        tickets = new SortedLinkedList<>();
        customers = new SortedLinkedList<>();

        try (BufferedReader reader = new BufferedReader(new FileReader("input_data.txt"))) {
            int numCustomers = Integer.parseInt(reader.readLine());
            for (int i = 0; i < numCustomers; i++) {
                String[] parts = reader.readLine().split(" ");
                customers.add(new Customer(parts[0], parts[1]));
            }

            int numTickets = Integer.parseInt(reader.readLine());
            for (int i = 0; i < numTickets; i++) {
                String name = reader.readLine();
                double price = Double.parseDouble(reader.readLine());
                tickets.add(new Ticket(name, price));
            }

            // 读取折扣信息
            double[] discounts = new double[3];
            for (int i = 0; i < 3; i++) {
                discounts[i] = Double.parseDouble(reader.readLine());
            }

            // 将折扣信息传递给每个票类对象
            for (Ticket ticket : tickets) {
                ticket.setDiscounts(discounts);
            }
        } catch (IOException e) {
            System.err.println("Error reading input_data.txt: " + e.getMessage());
        }
    }

    private static void displayMenu() {
        System.out.println("Menu:");
        System.out.println("f - Finish");
        System.out.println("t - Display tickets");
        System.out.println("c - Display customers");
        System.out.println("a - Add tickets to customer's account");
        System.out.println("r - Remove tickets from customer's account");
    }

    private static char getChoice() {
        System.out.print("Enter your choice: ");
        return scanner.nextLine().charAt(0);
    }

    private static void processChoice(char choice) {
        switch (choice) {
            case 'f':
                System.out.println("Finishing the program.");
                break;
            case 't':
                displayTickets();
                break;
            case 'c':
                displayCustomers();
                break;
            case 'a':
                addTicketsToCustomerAccount();
                break;
            case 'r':
                removeTicketsFromCustomerAccount();
                break;
            default:
                System.out.println("Invalid choice. Please try again.");
        }
    }

    private static void displayTickets() {
        System.out.println("Available Tickets:");
        for (Ticket ticket : tickets) {
            System.out.println(ticket.getName() + ": £" + ticket.getPrice());
        }
    }

    private static void displayCustomers() {
        System.out.println("Registered Customers:");
        for (Customer customer : customers) {
            System.out.println(customer.getFirstName() + " " + customer.getSurname() + " - Total Cost: £" + customer.getTotalCost() + ", Discounted Cost: £" + customer.getDiscountedTotalCost());
        }
    }

    private static void addTicketsToCustomerAccount() {
        System.out.print("Enter customer's first name: ");
        String firstName = scanner.nextLine();
        System.out.print("Enter customer's surname: ");
        String surname = scanner.nextLine();
        Customer customer = findCustomer(firstName, surname);

        if (customer == null) {
            System.out.println("Customer not found.");
            return;
        }

        System.out.print("Enter ticket name: ");
        String ticketName = scanner.nextLine();
        Ticket ticket = findTicket(ticketName);

        if (ticket == null) {
            System.out.println("Ticket not found.");
            return;
        }

        System.out.print("Enter number of tickets to add: ");
        int quantity = Integer.parseInt(scanner.nextLine());

        if (customer.addTickets(ticket, quantity)) {
            System.out.println("Tickets added successfully.");
            if (!customer.isEligibleForDiscount()) {
                writeLetter(customer, ticket, quantity);
            }
        } else {
            System.out.println("Failed to add tickets.");
        }
    }

    private static void removeTicketsFromCustomerAccount() {
        System.out.print("Enter customer's first name: ");
        String firstName = scanner.nextLine();
        System.out.print("Enter customer's surname: ");
        String surname = scanner.nextLine();
        Customer customer = findCustomer(firstName, surname);

        if (customer == null) {
            System.out.println("Customer not found.");
            return;
        }

        System.out.print("Enter ticket name: ");
        String ticketName = scanner.nextLine();
        Ticket ticket = findTicket(ticketName);

        if (ticket == null) {
            System.out.println("Ticket not found.");
            return;
        }

        System.out.print("Enter number of tickets to remove: ");
        int quantity = Integer.parseInt(scanner.nextLine());

        if (customer.removeTickets(ticket, quantity)) {
            System.out.println("Tickets removed successfully.");
        } else {
            System.out.println("Failed to remove tickets.");
        }
    }

    private static Customer findCustomer(String firstName, String surname) {
        for (Customer customer : customers) {
            if (customer.getFirstName().equals(firstName) && customer.getSurname().equals(surname)) {
                return customer;
            }
        }
        return null;
    }

    private static Ticket findTicket(String name) {
        for (Ticket ticket : tickets) {
            if (ticket.getName().equals(name)) {
                return ticket;
            }
        }
        return null;
    }

    private static void writeLetter(Customer customer, Ticket ticket, int quantity) {
        try (FileWriter writer = new FileWriter("letters.txt", true)) {
            writer.write("Dear " + customer.getFirstName() + " " + customer.getSurname() + ",\n");
            writer.write("Thank you for purchasing " + quantity + " " + ticket.getName() + " tickets.\n");
            writer.write("However, you currently do not qualify for a discount.\n");
            writer.write("To qualify for a discount, you need to purchase at least " + (6 - customer.getTotalQuantity()) + " more tickets.\n");
            writer.write("Best regards,\nNERD\n\n");
        } catch (IOException e) {
            System.err.println("Error writing to letters.txt: " + e.getMessage());
        }
    }
}

### 说明
1. **初始化数据**：从 `input_data.txt` 文件中读取客户和票务信息，并将它们存储在 `SortedLinkedList` 中。
2. **主菜单**：提供一个简单的文本菜单，让用户选择不同的操作。
3. **处理用户输入**：根据用户的选择调用相应的处理方法。
4. **显示票务信息**：列出所有可用的票务及其价格。
5. **显示客户信息**：列出所有注册客户的详细信息，包括他们购买的票务数量和总费用（如果有折扣）。
6. **添加票务到客户账户**：允许用户为特定客户添加指定数量的票务，并检查是否符合折扣条件。
7. **从客户账户移除票务**：允许用户从特定客户账户移除指定数量的票务。
8. **查找客户和票务**：辅助方法用于查找特定的客户和票务。
9. **写信函**：如果客户不符合折扣条件，生成并写入一封通知信函到 `letters.txt` 文件中。

这个实现满足了任务的要求，包括读取文件、处理用户输入、更新客户和票务信息以及生成通知信函。希望这对你有帮助！