C / C++ / MFC

gcc /tmp/BlXEG8NqhU.c -lm
/tmp/BlXEG8NqhU.c: In function 'main':
/tmp/BlXEG8NqhU.c:6:15: error: expected identifier or '(' before '&' token
    6 |     const int &a = 2;

There is the function `Sys_Milliseconds`:

    <pre>int	curtime;
    int Sys_Milliseconds (void)
    {
    	static int		base;
    	static qboolean	initialized = false;
    
    	if (!initialized)
    	{	// let base retain 16 bits of effectively random data
    		base = timeGetTime() & 0xffff0000;
    		initialized = true;
    	}
    	curtime = timeGetTime() - base;
    
    	return curtime;
    }

//...
    oldtime = Sys_Milliseconds();
    //...
    while (1) {
    		//...
    
    		while (PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) {
    			if (!GetMessage(&msg, NULL, 0, 0))
    				Com_Quit();
    			sys_msg_time = msg.time;
    			TranslateMessage(&msg);
    			DispatchMessage(&msg);
    		}
    
    		do {
    			newtime = Sys_Milliseconds();    			
    			time = newtime - oldtime;
    		} while (time < 1);
    //...
    }

//...
    oldtime = timeGetTime();
    //...
    while (1) {
    		//...
    
    		while (PeekMessage(&msg, NULL, 0, 0, PM_NOREMOVE)) {
    			if (!GetMessage(&msg, NULL, 0, 0))
    				Com_Quit();
    			sys_msg_time = msg.time;
    			TranslateMessage(&msg);
    			DispatchMessage(&msg);
    		}
    
    		do {
    			newtime = timeGetTime();    			
    			time = newtime - oldtime;
    		} while (time < 1);
    //...
    }

Hello!, this is my first post on this forum and i'm trying to understand how this works, so if this is not the proper way of asking for help or this is in the wrong subforum just let me know please!

I'm currently studying App Development, and as sort of a "final project" to pass the course, me and my group have to make a proyect that tracks both users and their data consumption.
Since we're restricted to using codeblocks and c language, I wanted to get some insight on how to improve the visual aspect of the cmd, and user experience overall.
I havent found many content of this kind online so any tutorial or explainatory about this subject would be very helpfull, since we havent been taught too much about this side of the coding, and I think this will be a great adition to the proyect, and learning experience overall.

Thanks!