How to check if a button is being pressed in C++

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I am making a regular window in windows (not a DOS window) and I want to check if a keyboard and a "on-screen button" is being pressed in a .cpp file (the window items are set up in a .h file), something like this:

while(true)
{
     if(keyboard button 1 is being pressed)
     {
           variable = variable + 1;
     }
}

or:

while(true)
{
     if("on-screen button" is being pressed)
     {
           variable = variable + 1;
     }
}

.

Also, how can i print a variable in a label?

[Modified: added pre tags...they are your friend!]

Posted 30-Dec-10 10:41am

Karsten Malmquist

Updated 25-Oct-11 0:15am

v5

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«_Superman_» · Answer 1 · 2010-12-30T13:36:00

Solution 1

Windows applications work differently in that it is event driven.
You do not keep polling and check for attributes as you have done.

So you generally have a dialog procedure in case of a Win32 application or a callback function in case of an MFC application for a button click. Here you write the code that needs to be done when the button is clicked.

To show the value of a variable in a label you can use the SetWindowText API.

Posted 30-Dec-10 13:36pm

«_Superman_»

Comments

Karsten Malmquist 31-Dec-10 7:24am

In a .h file I know how to check if a button is being clicked, but I want to have variables through the entire time the window is running, then I thought I might check it in a while loop because then the variables wont get destroyed by scope.
The problem is that in a .h file the variables get destroyed because of the rules of scope.
Sorry if you think i'm an idiot, but what do you mean by SetWindowText?
When I print out text I do like this:

this->label1->Text = L"Text";

jk chan · Answer 2 · 2010-12-30T19:52:00

Solution 2

You better learn some basic windows programming. http://www.winprog.org/tutorial/[^]
anyway you could know the key state using GetAsyncKeyState function

http://msdn.microsoft.com/en-us/library/ms646293(v=vs.85).aspx[^]

Posted 30-Dec-10 19:52pm

jk chan

Albert Holguin · Answer 3 · 2011-10-25T03:43:00

As Superman already stated, Windows programming is event driven. In order to be able to catch those events at all, you need to register as an application, create a messaging loop, and create an addressable Window somewhere that can accept the messages. Checking a state in an infinite loop is probably not the best way to approach your problem.