C#正则表达式将一些C#序列替换为<p>，一些替换为</p>

using System;
using System.Text.RegularExpressions;

class Program
{
    static void Main()
    {
        string input = "This is a sample text with C# code snippets like this: C#1, C#2, C#3.";
        
        // 定义正则表达式模式
        string pattern = @"C#(\d+)";
        
        // 使用正则表达式进行替换
        string result = Regex.Replace(input, pattern, match => {
            int number = int.Parse(match.Groups[1].Value);
            if (number % 2 == 0)
            {
                return $"<p>C#{number}</p>";
            }
            else
            {
                return $"</p>C#{number}";
            }
        });
        
        Console.WriteLine(result);
    }
}