GREETINGS
forgive me but I'm kinda new to multithreaded programming d=)

I'm just wondering how to implement a user interface in a
multithreaded programming environment or using cheap thread.

For example i have 2 threads. Thread A runs the user interface while
Thread B does other things. I mean how do i get the input from the
user through thread A since the two threads are switching controls.
I cant use scanf since it will wait for user input at the same time
suspending the execution of the other thread Thread B.

How can I run thread B on the background while thread A gets user
input?

Forgive me if my question is a bit trivial =)