Question

When I run my program the user can log in, but if the enter in a wrong user name, it runs a check username loop again, saying that they did not enter in a valid user name. This work perfectly fine except for one thing. Say they attempt to log in in three times and the third attempt is correct and the get prompted for a password. Once they input it it ask for a second password and then a third. It seems like it is completing the function for the other attempts. I can not think of a way to check for this. Any ideas.

If you look at it you can see that I am calling UserCheck inside of getNameIndex. I am almost positive this is where the error is occurring.

The Function that checks the users:

void User_Psw::UserCheck()
{
    // read from the database
    ifstream fin("dataBase.txt", ios::in);

    if( !fin.good() )
    {
        cout << "Failed to open database file." << endl;
        return;
    }

    while (fin >> username >> password)
    {
        Usernames.push_back(username);
        Password.push_back(password);
        ++sizeOfDatabase; // This may or may not be needed elsewhere.
    }

    // rest of the program
    cout << "Username: ";
    cin >> username;

    getNameIndex();

    cout << "Password: ";
    cin >> password;

    if(!PasswordMatches())
    {
        cout << "Access denied";
    }
    else
    {
        cout << "Success! You have logged in.";
    }
}

This is the username check function

void User_Psw::getNameIndex()
{
    userThere = false;

    for(int i=0; i < sizeOfDatabase; i++)
    {
        if (Usernames[i] == username)
        {
            index = i;
            userThere = true;
        }
    }
    if (userThere == false)
    {
        cout << "\nThat user name does not exsist. \n";
        cout << "Please try again. \n\n";
        UserCheck();
    }
}

Answer 1

The structure of your program is wrong.

Instead of getNameIndex calling UserCheck() again, you should have getNameIndex return a bool – true on success, false on failure. Run it inside of a loop, something like this:

bool success = false;

while (!success)
{
 cout << "Username: ";
 cin >> username;

 success = getNameIndex();
}

Also, instead of having global variables, you should pass them to the function. Something like:

success = getNameIndex(username);

and getNameIndex() shouldn’t do any I/O – the function that calls getNameIndex() should also be responsible for printing the error message. Imagine if you used getNameIndex() in a different context, such as when when the program is being run by another program or in an automated way – then printing to the console would be meaningless.