public interface IAccountDao{    string GetPassword(string id);}public interface IHash{    string GetHashResult(string password);}public class AccountDao : IAccountDao{    public string GetPassword(string id)    {        throw new NotImplementedException();    }}public class Hash : IHash{    public string GetHashResult(string password)    {        throw new NotImplementedException();    }}public class Validation{    private IAccountDao _accountDao;    private IHash _hash;    public Validation(IAccountDao dao, IHash hash)    {        this._accountDao = dao;        this._hash = hash;    }    public bool CheckAuthentication(string id, string password)    {        // 取得資料中，id對應的密碼                               var passwordByDao = this._accountDao.GetPassword(id);        // 針對傳入的password，進行hash運算        var hashResult = this._hash.GetHashResult(password);        // 比對hash後的密碼，與資料中的密碼是否吻合        return passwordByDao == hashResult;    }}

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