C++ Classes and accessing

Question

I am getting an error, and being new to C++ I have absolutely no idea what it means, and I also know that you should not get passwords this way, but it is the only way I could think of to test myself in more difficult areas of C++, I have just started this and already get stumped by this.

class user
{
private:
    int security;
    string password;
public:
    string username, email;
    int age;
    string signup()
    {
        int num;
        cout << "Welcome new user!\nPlease enter your username:\n";
        cin >> username;
        cout << "What is your email?\n";
        cin >> email;
        cout << "What is your age?\n";
        cin >> age;
        cout << "Make a password:\n";
        cin >> password;
        cout << "Enter a number:\n";
        cin >> num;
        security = mnet::random(num);
        cout << "Your security code is " << security << endl;
        return username;


    }
};
int main()
{
    string LorS;
    user cprofile;
    cout << "Welcome to MatrixNet! Login or Sign up?[L/S]\n";
    cin >> LorS;
    if(LorS == "S" || LorS == "s") {
        cprofile = cprofile.signup();
    }



    return 0;
}

The errors I am getting:

In function 'int main()':|
|55|error: no match for 'operator=' (operand types are 'user' and 'std::__cxx11::string {aka std::__cxx11::basic_string<char>}')

|20|note: candidate: user& user::operator=(const user&)

|20|note:   no known conversion for argument 1 from 'std::__cxx11::string {aka std::__cxx11::basic_string<char>}' to 'const user&'

|20|note: candidate: user& user::operator=(user&&)

|20|note:   no known conversion for argument 1 from 'std::__cxx11::string {aka std::__cxx11::basic_string<char>}' to 'user&&'|

Line 55:

    cprofile = cprofile.signup();

Answer 1

signup() returns a std::string , but you're trying to assign it to a user , which as the compiler is telling you (rather cryptically, mind you), you cannot do:

 note: no known conversion for argument 1 from 'std::__cxx11::string {aka std::__cxx11::basic_string}' to 'const user&'` 

I'd suggest dropping the assignment on line 55 and simply calling cprofile.signup() . In object-oriented programming, objects are stateful, which means they contain state, such as your security , password , etc. Your signup() function sets this state on the object it's called on, so by simply saying cprofile.signup() , cprofile modifies itself appropriately. This is also the basis for class encapsulation .

Answer 2

You cannot assign a string to a class object as you attempted in writing this statement:

cprofile = cprofile.signup();

if you simply wanted to store the string returned by your signup function then just declare a new string variable and use it:

string LorS;
string userName;
user cprofile;
cout << "Welcome to MatrixNet! Login or Sign up?[L/S]\n";
cin >> LorS;
if(LorS == "S" || LorS == "s") {
    userName = cprofile.signup();
}

Answer 3

Signup simply returns the username as a string, as well as setting up your account. Thus, trying to assign cprofile to the return value of signup () makes no sense without a constructor that receives a std::string. It looks like you want the side effects of signup not the return value, so just run cprofile.signup(). If you didn't understand this, you probably need to learn more.