using System;

public class Program

{

    public static void Main()

    {

        Console.WriteLine("請輸入使用名稱:");

        string username,password;

        username=Console.ReadLine();

        if(username=="馬壯")

        {

            Console.WriteLine(username+"您好");

            Console.Write("請輸入密碼:");

            password=Console.ReadLine();

            if( (password=="egg566")||

               (password=="EGG566"))

            {

              Console.WriteLine("歡迎進入本系統");

            }

            else if (password!="egg566")

            {

              Console.WriteLine("密碼錯誤");

            }

        }

        else if(username=="徐強")

        {

            Console.WriteLine(username+"您好");

            Console.Write("請輸入密碼:");

            password=Console.ReadLine();

            if( (password=="dog123")||

               (password=="DOG123"))

            {

              Console.WriteLine("歡迎進入本系統");

            }

            else if (password!="dog123")

            {

              Console.WriteLine("密碼錯誤");

            }

        }

    }

}

​