如何在c#中编写和更新存储在文本文件中的用户分数？

using System.IO;

string filePath = "scores.txt";
StreamWriter writer = new StreamWriter(filePath);
writer.Close();

using System;
using System.IO;

string filePath = "scores.txt";

// 读取用户分数
public static int ReadScore(string userName)
{
    int score = 0;
    using (StreamReader reader = new StreamReader(filePath))
    {
        string line;
        while ((line = reader.ReadLine()) != null)
        {
            string[] parts = line.Split(':');
            if (parts.Length == 2 && parts[0] == userName)
            {
                int.TryParse(parts[1], out score);
                break;
            }
        }
    }
    return score;
}

// 更新用户分数
public static void UpdateScore(string userName, int newScore)
{
    string tempFile = Path.GetTempFileName();
    using (StreamReader reader = new StreamReader(filePath))
    using (StreamWriter writer = new StreamWriter(tempFile))
    {
        string line;
        bool updated = false;
        while ((line = reader.ReadLine()) != null)
        {
            string[] parts = line.Split(':');
            if (parts.Length == 2 && parts[0] == userName)
            {
                writer.WriteLine($"{userName}:{newScore}");
                updated = true;
            }
            else
            {
                writer.WriteLine(line);
            }
        }
        if (!updated)
        {
            writer.WriteLine($"{userName}:{newScore}");
        }
    }
    File.Delete(filePath);
    File.Move(tempFile, filePath);
}

string userName = "John";
int currentScore = ReadScore(userName);
Console.WriteLine($"当前分数：{currentScore}");

int newScore = 100;
UpdateScore(userName, newScore);
Console.WriteLine("分数已更新。");

int updatedScore = ReadScore(userName);
Console.WriteLine($"更新后的分数：{updatedScore}");