string setPass(bool show_asterisk = true)
{
    const char BACKSPACE = 8;//ASCII code for BACKSPACE Key
    const char ENTER = 13;//ASCII code for ENTER Key
    string pass = " ";//initialize string
    char c = ' ';//initialize character

    while ((c = _getch()) != ENTER)
    {
        if (c == BACKSPACE)
        {
            if (pass.length() != 0)
            {
                if (show_asterisk)
                   cout << "b b";
                pass.resize(pass.length() - 1); //resize the length of pass
            }
        }
        else if (c == 0 || c == 224)//when player press esc key
        {
            _getch();
            continue;
        }
        else
        {
            pass.push_back(c);
            cout << '*';
        }
    }
    cout << endl;
    return pass;
}

cout << "==================" << endl;
cout << "      login       " << endl;
cout << "  ID:";
cin >> id;
cout << "  Password:";
cin >> pwd;
pwd = setPass();