(Windows)Can I get the program to be changed or be stopped while it is running?

I am now writing a win32 program in C++.
I want to show my running process on the window, just like time is flowing.

For example, this code

int a=0;
for(int i=0;i<10;i++)
{
  a++;//The change in "a" can be seen on the window.
  Sleep(1*1000);
}

But I’ve found that if I want to show this process, like clicking a button and a changing number appears on the screen, then the program needs to be running all the time. At this point, I don’t have a way to do anything else, like clicking on another button.

So I realized I needed an operation that could interrupt the current process. But I went through a lot of information and found that only the fork() function of the Linux system can meet my needs. But I’m using Windows now, so what other ways can I achieve this?
Sincerely look forward to your reply.

>Solution :

You want to create a timer with SetTimer. Then watch for the WM_TIMER messages and update the screen then. This is the standard way of achieving what you described.