C++ simple brute force project password input method

I am trying to create a simple C++ brute forcing program to crack small passwords-maybe like 3-4 characters long, (as a science fair project) just to show people how it works, i.e. my topic is mainly about cyber security and data breach vulnerability and stuff.

So I got the brute forcing part covered, but what I want to change is that instead of asking users to enter their password within my program itself, I was wondering if it was possible to make a, say, an HTML page with a login screen, and the entered password is then saved to a txt file which I can then open from my program for the brute forcing part.

What I am trying to say is that most people trying this out wont be so convinced entering passwords into an output box. They might wonder if I had just printed out the password they entered. I saw other people's programs but all they did was cin>>password and then started the brute forcing part. The user does not know if his password was cracked or the programmer just did cout<< password.

So it would help me a lot by letting me know of methods in which I can achieve this(not just with HTML, anything is fine, as long as its not an output box).

Sorry for the long question! Just wanted to make sure I covered all the info. Please help me!!! P.S: I'm just a student (1 and a half years into C++ :)), so please try to keep it as simple as you can. Thanks in advance!!