Answer 1

You can create login form with HTML, add stylish looks with CSS and interactivity with JavaScript, and use PHP and SQL to use data. It is uncommon for people to choose C++ for web coding. Even possible, it would most likely require you to do or create functionalities already provided by HTML.

I guess you'd better settle with HTML and other web related tools, it would save you a lot of unnecessary extra works, just my personal opinion though : )