Key Presses?

[967L1hU5]

How can I make it so the user doesn't have to press enter when entering something on a console program? Like for example, the program says "Press Q to quit", the user only has to press "Q", and not "Q" than ENTER? I read something about it before, but I didn't pay much attention to it before. Could someone explain how to do it or post a reference that explains it?

[hanst99]

I don't think there's a way to do this with standard C++, but there are various methods to get keypresses - on windows you could use the WinAPI:

#include <iostream>
#include <windows.h>

int main()
{
std::cout<<"Press Q to exit"<<std::endl;
while(!(GetASyncKeyState(VK_Q)>0));
return 0;
}
/*not 100% sure if it was like that, has been a while since I last used the WinAPI
 and I don't have access to windows right now*/

http://msdn.microsoft.com/en-us/library/windows/apps/ms646293%28v=vs.85%29.aspx

[967L1hU5]

When I compile, I get two errors:

error: 'GetASyncKeyState' was not declared in this scope
error: 'VK_Q' was not declared in this scope

[hanst99]

Try adding <winuser.h> - though technically it should be included by windows.h if I'm not mistaken.

[967L1hU5]

Already tried that from
http://msdn.microsoft.com/en-us/library/windows/apps/ms646293%28v=vs.85%29.aspx

Got the same result.

[hanst99]

Well, that's strange- what OS/compiler are you using?

[967L1hU5]

Windows 7 Ultimate x86, with Codeblocks. GNU GCC Compiler.

[hanst99]

MinGW or Cygwin?

[967L1hU5]

MinGW.

[hanst99]

Does

MessageBox(NULL, "Hello World!", "Test",  MB_OK);

work?

[967L1hU5]

Yeah.

P.S. That's some nifty code!

[hanst99]

Ok, now I'm confused. If that works, GetASyncKeyState should too.

[967L1hU5]

Any ideas on what it might be?

[Athar]

It's Async.
Using that function isn't all that much of a good idea, since it registers key presses even outside the window.
That's not the expected behavior and some antivirus software doesn't like programs that use the function either.
(and without a "Sleep" it would burn all CPU time it can get until someone finally hits a key)

_getch should do the trick:
http://msdn.microsoft.com/de-de/library/078sfkak%28v=vs.80%29.aspx

[hanst99]

Async. Of course. I remember making that typo all the time in the past too.

I never said it was good code, I just said it was a conceivable way to do it. But yeah, I suppose _getch is better for the purposes of the OP.


_{doesn't explain why VK_Q isn't recognized though}

[967L1hU5]

Thanks!