Question

所以我对c ++很陌生，而且它会破坏我的思想。所以我需要帮助。我试图在String object中搜索vector<Objects>并查看它们是否相等。正在搜索，我决定使用c ++ 11 lamba表达式，它一直给我错误：

    Severity    Code    Description Project File    Line    Suppression State
Error   C3867   'User::getEmail': non-standard syntax; use '&' to create a pointer to member    EmailServerClientApp    c:\users\user\desktop\emailserverclientapp\emailserverclientapp\guinterface.cpp 110 

    Severity    Code    Description Project File    Line    Suppression State
Error   C2678   binary '==': no operator found which takes a left-hand operand of type 'overloaded-function' (or there is no acceptable conversion) EmailServerClientApp    c:\users\user\desktop\emailserverclientapp\emailserverclientapp\guinterface.cpp 110

我创建了一个重载运算符（或者至少我对c ++的了解，我认为我做过）。看不出这个有什么不对。

这是我的用户类：

    private:
    string userName;
    string password;
    string email;

public:
    User();
    User(string name, string pass, string e);

    void setUserName(string name);
    void setPassword(string pass);
    void setEmail(string e);
    bool numberInString(const std::string& s);
    void print()const;

    User &operator=(User other)
    {
        std::cout << "copy assignment of Email\n";
        std::swap(userName, other.userName);
        std::swap(password, other.password);
        std::swap(email, other.email);
        return *this;
    }
    friend bool operator ==(const User &c1, const string &e);



    string getUserName()const;
    string getPassword()const;
    string getEmail()const;

    ~User();
};

创建运算符以检查是否等于：

bool operator==(const User & c1, const string& e )
{
    return (c1.email == e);

}

这个方法在这里我试图在向量中找到实际的电子邮件：

bool checkIfUserExists(vector<User> v,string email, string password) {/* using c++11 lamba expression to find an 
                                                                      element in vector matching my string object 
                                                                      */
    vector<User>::iterator it = std::find_if(v.begin(), v.end(), [&email](const User&c1) {return c1.getEmail == email; });

        if (it != v.end())
        {
            return true;
        }
        else {
            return false;
        }
}

我在做错了什么。我需要帮助。很快就会哭。提前谢谢

Answer 1

{return c1.getEmail == email;}

getEmail()是一个类方法，而不是类成员。正确的语法应该是：

{return c1.getEmail() == email;}

比较字符串对象等于向量中的元素

1 个答案: