Thread: getch(); problem!!?!?!

Where exactly do you expect the input to come from? getch() reads from stdin [or a similar input - but lets make it stdin at the moment], when you don't have a window, there's no console to feed your keypresses through to stdin.

If you want to do this, you'll POSSIBLY be able to do it by using the Windows API, but I'm 99.9% sure that you can't read from a console when the window of that console is hidden, becuase the window itself is responsible for transforming a generic keypress into a "stdin" input.

Could of course be that I'm wrong.

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Mats

Define "doesn't work." getch returns an int and you are attempting to store it into a string. Do you get no warnings/errors at all? If this is a C++ program you should also be including <string>, and <cstdio> instead of <stdio.h> and <cstdlib> instead of <stdlib.h>.

Originally Posted by hk_mp5kpdw

Define "doesn't work." getch returns an int and you are attempting to store it into a string. Do you get no warnings/errors at all? If this is a C++ program you should also be including <string>, and <cstdio> instead of <stdio.h> and <cstdlib> instead of <stdlib.h>.

And probably shouldn't have "using namespace std" BEFORE the includes either!

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Mats

Originally Posted by matsp

And probably shouldn't have "using namespace std" BEFORE the includes either!

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Mats

Actually, conio.h, stdio.h, and every other include after davidboja's using namespace std all use the global namespace. Right now, only iostream uses std::, and as the using directive is after that header file, everything's fine and dandy.

Of course, if the code was changed to use <cstdio> instead of <stdio.h> etc, then those c* header files would have to go before the using directive. Presumably this is what you meant, but I just thought I'd clarify.

Originally Posted by dwks

Actually, conio.h, stdio.h, and every other include after davidboja's using namespace std all use the global namespace. Right now, only iostream uses std::, and as the using directive is after that header file, everything's fine and dandy.

Of course, if the code was changed to use <cstdio> instead of <stdio.h> etc, then those c* header files would have to go before the using directive. Presumably this is what you meant, but I just thought I'd clarify.

Actually, I was more trying to say that "You should never put using namespace ..."[1] before a header-file, but yes, only on some headerfiles does it make a noticable difference.

[1] "Never say never", but in my opinion, there is, AFAIK, no good reason to put a using namespace ... before any include file.
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Mats

Originally Posted by davidboja

but when i don't hide cmd it work!!!

And I said:

Where exactly do you expect the input to come from? getch() reads from stdin [or a similar input - but lets make it stdin at the moment], when you don't have a window, there's no console to feed your keypresses through to stdin.

If you want to do this, you'll POSSIBLY be able to do it by using the Windows API, but I'm 99.9% sure that you can't read from a console when the window of that console is hidden, becuase the window itself is responsible for transforming a generic keypress into a "stdin" input.

Could of course be that I'm wrong.

That pretty much confirms what I say: You need to have a command window to receive data through the console device. Which is hardly surprising. [Well, it's not surprising to me anyways].

What are you actually trying to do? [Big picture, not "read a character from the keyboard" type answer].

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Mats

Originally Posted by davidboja

but when i don't hide cmd it work!!!

And what do you want? Read a character from a console window that isn't there?

To clarify: Windows uses "messages" to indicate keypresses. The "console window" is used to receive these messages, and translate it into "standard input". Without the window there, Windows will just send the message about the keypress to the next window, which is perhaps your desktop, a web-browser, MS Word or whatever is left on the screen. Whether that application actually does anything with the message about the keypress is obviously up to that application.

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Mats

Originally Posted by matsp

[1] "Never say never", but in my opinion, there is, AFAIK, no good reason to put a using namespace ... before any include file.
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Mats

Never, indeed. What if the contents of the header file require some namespace to be brought into the global namespace? . . . "Who is the idiot who designed this header file, anyway?"

Note that you can detect keypresses sent to other applications. But you have to use special functions like GetAsyncKeyPress(), and it can be a bit of a pain.